NEET-UG 2017 Question Paper Solutions

SOLUTIONS

2017 NEET EXAM

NEET-UG 2017 Question Paper Solutions

2017

NEET-UG

CBSE EXAMINATION PAPER-2017

NEET-ZOOLOGY

(Solved)

Time allowed : 3 hours

Maximum Marks : 721

General Instructions :

Read the following instructions carefully and follow them :

  1. This question paper contains 180 questions. All questions are compulsory.
  2. This question paper is divided into 1 sections.
  3. Section A – questions number 1 to 180 are multiple choice questions
  4. There is no overall choice given in the question paper. However, an internal choice has been provided in few questions.
  5. Use of calculator is NOT allowed.

Section A

Question 1.

A physical quantity of the dimensions of length that can be formed out of c, G and e²/4πϵ₀ [c is velocity of light, G is universal constant of gravitation and e is charge

[4 Marks]
  • (A) 1/c² [e²/G4πϵ₀]⁻¹ᐟ²
  • (B) 1/c G e²/4πϵ₀
  • (C) 1/c² [ G e²/4πϵ₀]⁻¹ᐟ²
  • (D) c² [Ge²/4πϵ₀]¹ᐟ²
Explanation:

Let dimensions of length is related as,

[L] = [c]ˣ [G]ʸ [ e²/4πϵ₀ ]ᶻ

⇒ e²/4πϵ₀ = [ML³T⁻²]

[L] = [LT⁻¹]ˣ [M⁻¹L³T⁻²]ʸ [ML³T⁻²]ᶻ

[L] = [Lˣ⁺³ʸ⁺³ᶻ M⁻ʸ⁺ᶻ T⁻ˣ⁻²ʸ⁻²ᶻ]

Comparing both sides

−y + z = 0 ⇒ Z ...(i)

x + 3y + 3z = 1 ...(ii)

−x − 4z = 0 (∵ y = z) ...(iii)

From (i), (ii) and (iii)

z = y = −1/2 ; x = −2

Hence,

[L] = c⁻² [ G · e²/4πϵ₀ ]¹ᐟ²

Question 2.

Preeti reached the metro station and found that the escalator was not working. She walked up the stationary escalator in time t₁. On other days, if she remains stationary on the moving escalator, then the escalator takes her up in time t₂. The time taken by her to walk up on the moving escalator will be

[4 Marks]
  • (A) t₁ − t₂
  • (B) t₁t₂/(t₂ − t₁)
  • (C) (t₁ + t₂)/2
  • (D) t₁t₂/(t₂ + t₁)
Explanation:
Let the distance be ‘d’ time taken by Preeti to travel up
the stationary escalator = t₁

Velocity of Preeti w.r.t. elevator

v₁ = d/t₁

Since the distance is same let the time taken when Preeti
stands on the moving escalator = t₂.

Velocity of elevator w.r.t. ground

v₂ = d/t₂

The net velocity of Preeti w.r.t. ground

v = v₁ + v₂

d/t = d/t₁ + d/t₂

1/t = 1/t₁ + 1/t₂

t = t₁t₂/(t₁ + t₂)

(time taken by Preeti to walk up the
moving escalator)
Question 3.

The x and y coordinates of the particle at any time are
x = 5t − 2t² and y = 10t respectively, where x and y are in me

[4 Marks]
  • (A) 5 m/s²
  • (B) 0
  • (C) −8 m/s²
  • (D) −4 m/s²
Explanation:

Given:

x = 5t − 2t² y = 10t

vₓ = dx/dt = 5 − 4t
vᵧ = dy/dt = 10

aₓ = dvₓ/dt = −4 aᵧ = dvᵧ/dt = 0

𝐚⃗ = aₓî + aᵧĵ

𝐚⃗ = −4î m/s²

Hence, acceleration of particle at (t = 2 s) = −4 m/s²

Question 4.

Two blocks A and B of masses 3m and m respectively are connected by a massless and inextensible string. The whole system is suspended by a massless spring as shown in figure. The magnitudes of acceleration of A and B immediately after the string is cut, are respectively:

[4 Marks] Diagram 1 – NEET-UG 2017 Question Paper Solutions
  • (A) g/3,g
  • (B) g/3,g/3
  • (C) g,g/3
  • (D) g,g
Explanation:

Before cutting the string

kx = T + 3mg ...(i)

T = mg ..(ii)

Force on spring,

⇒ kx = 4mg

After cutting the string T = 0

For block A:

3ma_A = 4mg − 3mg

a_A= (4mg − 3mg)/3m = g/3

a_A = g/3

For block B:

ma_B= mg

a_B = g

Diagram 2 – NEET-UG 2017 Question Paper Solutions
Question 5.

One end of string of length l is connected to a particle of mass 'm' and the other end is connected to a small peg on a smooth horizontal table. If the particle moves in circle with speed 'v' then the net force on the particle (directed towards centre) will be (T represents the tension in the string):

[4 Marks]
  • (A) T + mv²/l
  • (B) T − mv²/l
  • (C) T
  • (D) Zero
Explanation:

Net force on particle in uniform circular motion is centripetal force (mv²/ℓ) which is provided by tension in string so the net force will be equal to tension i.e., T.

Question 6.

Two discs of same moment of inertia rotating about their regular axis passing through centre and perpendicular to the plane of disc with angular velocities ω₁ and ω₂. They are brought into contact face to face coinciding the axis of rotation. The expression for loss of energy during this process is:

[4 Marks]
  • (A) I(ω₁ − ω₂)²
  • (B) 1/4 I(ω₁ − ω₂)²
  • (C) 1/2 I(ω₁ + ω₂)²
  • (D) 1/8 I(ω₁ − ω₂)²
Explanation:

Here, Iω₁ + |ω₂ = 2Iω

⇒ ω = (ω₁ + ω₂)/2

(K.E.)ᵢ = 1/2 Iω₁² + 1/2 Iω₂²

(K.E.)𝒇 = 1/2 × 2Iω² = I[(ω₁ + ω₂)/2]²

Loss in K.E. = (K.E.)𝒇 ᵢ − (K.E.) ᵢ = 1/4 I(ω₁ − ω₂)²

Question 7.

A rope is wound around a hollow cylinder of mass 3 kg and radius 40 cm. What is the angular acceleration of the cylinder if the rope is pulled with a force of 30 N?

[4 Marks]
  • (A) 25 rad/s²
  • (B) 0.25 rad/s²
  • (C) 5 m/s²
  • (D) 25 m/s²
Explanation:

Given, mass of cylinder m = 3 kg

R = 40 cm = 0.4 m

F = 30 N ; α = ?

As we know, torque τ = Iα

F × R = MR²α

α = (F × R)/(MR²)

α = (30 × 0.4)/(3 × (0.4)²)

or, α = 25 rad/s²

Diagram 3 – NEET-UG 2017 Question Paper Solutions
Question 8.

Two astronauts are floating in gravitation free space after having lost contact with their spaceship. The two will

[4 Marks]
  • (A) keep floating at the same distance between them.
  • (B) become stationary
  • (C) move towards each other.
  • (D) move away from each other.
Explanation:

Both the astronauts are in the condition of ‘weightlessness. Gravitational force between them pulls towards each other. Hence Astronauts move towards each other under mutual gravitional force.

Question 9.

The acceleration due to gravity at a height 1 km above the earth is the same as at a depth d below the surface of earth. Then

[4 Marks]
  • (A) d = 3/2 km
  • (B) d = 1 km
  • (C) d = 2 km
  • (D) d = 1/2 km
Explanation:

Above earth surface Below earth surface
gₕ = g (1 − 2h/Rₑ) g_d = g (1 − d/Rₑ)
According to question, gₕ = g_d
g (1 − 2h/Rₑ) = g (1 − d/Rₑ)
Clearly,
d = 2h = 2 km

Question 10.

The bulk modulus of a spherical object is 'B'. If it is subjected to uniform pressure 'p', the fractional decrease in radius is

[4 Marks]
  • (A) 3p/B
  • (B) p/3B
  • (C) p/3B
  • (D) p/B
Explanation:

Bulk modulus is given by
B = p/(ΔV/V)
or
ΔV/V = p/B
3 ΔR/R = p/B (here, ΔR/R = fractional decrease in radius)

⇒ ΔR/R = p/3B

Question 11.

A U tube with both ends open to the atmosphere, is partially filled with water. Oil, which is immiscible with water, is poured into one side until it stands at a distance of 10 mm above the water level on the other side. Meanwhile the water rises by 65 mm from its original level (see diagram).

[4 Marks] Diagram 4 – NEET-UG 2017 Question Paper Solutions
  • (A) 928 kg m⁻³
  • (B) 800 kg m⁻³
  • (C) 425 kg m⁻³
  • (D) 650 kg m⁻³
Explanation:

Here, hₒᵢₗ × ρₒᵢₗ × g = h(water)subscript × ρ(water)subscript × g
ρ₀g × 140 × 10⁻³ = ρ_w g × 130 × 10⁻³
ρₒᵢₗ = 130/140 × 10³ ≈ 928 kg/m³

[∵ ρ_w = 1 kgm⁻³]

Question 12.

Two rods A and B of different materials are welded together as shown in figure. Their thermal conductivities are K₁ and K₂. The thermal conductivity of the composite rod will be :

[4 Marks] Diagram 5 – NEET-UG 2017 Question Paper Solutions
  • (A) (K₁ + K₂)/2
  • (B) 2(K₁ + K₂)
  • (C) K₁ + K₂
  • (D) 3(K₁ + K₂)/2
Explanation:
quivalent thermal conductivity of the composite rod in parallel combination will be,
K = K₁A(T₁ − T₂)/d + K₂A(T₁ − T₂)/d
K_EQ 2A(T₁ − T₂)/d = A(T₁ − T₂)/d [K₁ + K₂]
Hence equivalent thermal conductivities for two rods of
equal area is given by
K_EQ = (K₁ + K₂)/2


 
Question 13.

A spherical black body with a radius of 12 cm radiates 450 watt power at 500 K. If the radius were halved and the temperature doubled, the power radiated in watt would be

[4 Marks]
  • (A) 450
  • (B) 1000
  • (C) 1800
  • (D) 225
Explanation:

Given r₁ = 12 cm, r₂ = 6 cm
T₁ = 500 K and T₂ = 2 × 500 = 1000 K
P₁ = 450 watt
Rate of power loss P ∝ r²T⁴
P₁/P₂ = r₁²T₁⁴/r₂²T₂⁴
P₂ = P₁(r₂²T₂⁴)/(r₁²T₁⁴)
Solving we get,
P₂ = 1800 watt

Question 14.

Thermodynamic processes are indicated in the following diagram:

[4 Marks] Diagram 6 – NEET-UG 2017 Question Paper Solutions
  • (A) P→D, Q→B, R→A, S→C
  • (B) P→A, Q→C, R→D, S→B
  • (C) P→C, Q→A, R→D, S→B
  • (D) P→C, Q→D, R→B, S→A
Explanation:

Process I volume is constant hence, it is isochoric.
In process IV, pressure is constant hence, it is isobaric

Question 15.

A carnot engine having an efficiency of 1/10 as heat engine, is used as a refrigerator. If the work done on the system is 10 J, the amount of energy absorbed from the reservoir at lower temperature is

[4 Marks]
  • (A) 90 J
  • (B) 99 J
  • (C) 100 J
  • (D) 1 J
Explanation:
Given, efficiency of engine,

η = 1/10

work done on system W = 10 J

Coefficient of performance of refrigerator,

β = Q₂/W = (1 − η)/η

= (1 − 1/10)/(1/10)

= (9/10)/(1/10)

= 9

Energy absorbed from reservoir,

Q₂ = βW

Q₂ = 9 × 10 = 90 J
Question 16.

A gas mixture consists of 2 moles of O₂ and 4 moles of Ar at temperature T. Neglecting all vibrational modes, the total internal energy of the system is:

[4 Marks]
  • (A) 9RT
  • (B) 11RT
  • (C) 15RT
  • (D) 4RT
Explanation:

Internal energy of the system is given by
U = f/2 nRT
Degree of freedom
F_diatomic = 5
F_monatomic₎ = 3
and, number of moles
n(O₂) = 2
n(Ar) = 4
U_total = 5/2 (2)RT + 3/2 (4)RT = 11RT

Question 17.

A particle executes linear simple harmonic motion with an amplitude of 3 cm. When the particle is at 2 cm from the mean position, the magnitude of its velocity is equal to that of its acceleration. Then its time period in seconds is

[4 Marks]
  • (A) √5/π
  • (B) 2π/√3
  • (C) 4π/√5
  • (D) √5/2π
Explanation:
Given, Amplitude A = 3 cm
When particle is at x = 2 cm
According to question, magnitude of velocity = acceleration
ω√(A² − x²) = xω²
√(3)² − (2)² = 2(2π/T)
√5 = 4π/T
⇒ T = 4π/√5 


 
Question 18.

A spring of force constant k is cut into lengths of ratio 1 : 2 : 3. They are connected in series and the new force constant is k'. Then they are connected in parallel and force constant is k''. Then k' : k'' is

[4 Marks]
  • (A) 1:14
  • (B) 1:6
  • (C) 1:9
  • (D) 1:11
Explanation:
Let ℓ be the complete length of spring.
Length when cut in ratio 1 : 2 : 3 are
ℓ/6, ℓ/3 and ℓ/2
Spring constant (k) ∝ 1/length (ℓ)
Spring constant for given segments
k₁, 6k, k₂ =3k and  k₃ =2k
When they are connected in series
1/k′ = 1/6k + 1/3k + 1/2k
⇒ 1/k′ = 6/6k
∴ Force constant k′ = k
And when they are connected in parallel
k″ = 6k + 3k + 2k
⇒ k″ = 11k
Then the ratios
k /k″ =1/11 i.e.,  1 : 11
Question 19.

The two nearest harmonics of a tube closed at one end and open at other end are 220 Hz and 260 Hz. What is the fundamental frequency of the system?

[4 Marks]
  • (A) 30 Hz
  • (B) 10 Hz
  • (C) 40 Hz
  • (D) 20 Hz
Explanation:

Difference in two successive frequencies of closed pipe, 2v/4l ⇒ 260 - 220= 40 Hz

or
2v/4ℓ = 40 Hz
⇒ v/4ℓ = 20 Hz
Which is the fundamental frequency of system of closed organ pipe.

Question 20.

Two cars moving in opposite directions approach each other with speed of 22 m/s and 16.5 m/s respectively. The driver of the first car blows a horn having a frequency 400 Hz. The frequency heard by the driver of the second car is (velocity of sound 340 m/s):

[4 Marks]
  • (A) 361 Hz
  • (B) 411 Hz
  • (C) 448 Hz
  • (D) 350 Hz
Explanation:

As we known from Doppler’s Effect
fₐₚₚₐᵣₑₙₜ = f₀ [(v + v₀)/(v − vₛ)] = 400 [(340 + 16.5)/(340 − 22)]
fₐₚₚₐᵣₑₙₜ = 448 Hz

Diagram 7 – NEET-UG 2017 Question Paper Solutions
Question 21.

Suppose the ratio of proton and electron differ slightly. One of them is −e, the other is (e + Δe). If the net of electrostatic force and gravitational force between two hydrogen atoms placed at a distance d (much greater than atomic size) apart is zero, then Δe is of the order of [Given mass of hydrogen mₕ = 1.67 × 10⁻²⁷ kg]

[4 Marks]
  • (A) 10⁻⁴⁷ C
  • (B) 10⁻²⁰ C
  • (C) 10⁻³⁷ C
  • (D) 10⁻²³C
Explanation:

Net charge on one H atom = −e + (e + Δe) = Δe
According to question, the net electrostatic force (F_E) = gravitational force (F_G)
F_E = F_G
or
1/4πϵ₀ · Δe²/d² = Gm²/d²
⇒ Δe = m√(G/k) [∵ 1/4πϵ₀ = k = 9 × 10⁹]
= 1.67 × 10⁻²⁷ √(6.67 × 10⁻¹¹ / 9 × 10⁹)
Δe ≈ 1.436 × 10⁻³⁷ C

Question 22.

The diagrams below show regions of equipotentials.

A positive charge is moved from A to B in each diagram.

[4 Marks] Diagram 8 – NEET-UG 2017 Question Paper Solutions
  • (A) In all the four cases the work done is the same
  • (B) Maximum work is required to move q in figure (c)
  • (C) Minimum work is required to move q in figure (a)
  • (D) Maximum work is required to move q in figure (b)
Explanation:

As the regions are of equipotentials, so Work done

W = qΔV

ΔV is same in all the cases hence work done will also be same in all the cases.

Question 23.

A capacitor is charged by a battery. The battery is removed and another identical uncharged capacitor is connected in parallel. The total electrostatic energy of resulting system:

[4 Marks]
  • (A) remains the same
  • (B) decreases by a factor of 2
  • (C) increases by a factor of 2
  • (D) increases by a factor of 4
Explanation:

When battery is replaced by another uncharged

capacitor

As uncharged capacitor is connected parallel

So, C′ = 2C

and V_c = (q₁ + q₂)/(C₁ + C₂)

V_c = (q + 0)/(C + C) = CV/(C + C) [∵ q = CV]

⇒ V_c = V/2

Initial Energy of system, Ui = 1/2 CV² ...(i)

Final energy of system, U_f = 1/2 (2C)(V/2)²

= 1/2 CV² (1/2) ...(ii)

From equation (i) and (ii)

U_f = 1/2 Ui

i.e., Total electrostatic energy of resulting system decreases by a factor of 2.

Diagram 9 – NEET-UG 2017 Question Paper Solutions
Question 24.

The resistance of a wire is 'R ohm. If it is melted and stretched to 'n' times its original length, its new resistance will be:-

[4 Marks]
  • (A) R/n²
  • (B) nR
  • (C) n²R
  • (D) R/n
Explanation:

We know that,

R = ρℓ/A

or

R = ρℓ²/Volume ∝ ℓ²

According to question ℓ₂ = nℓ₁

R₂/R₁ = n²ℓ₁²/ℓ₁²

or,

R₂/R₁ = n²

⇒ R₂ = n²R₁

Question 25.

A potentiometer is an accurate and versatile device to make electrical measurements of E.M.F. because the method involves

[4 Marks]
  • (A) Cells
  • (B) A combination ofcells, galvanometer and resistances
  • (C) A condition of no current flow through the galvanometer
  • (D) Potential gradients
Explanation:

Reading of potentiometer is accurate because during taking reading it does not draw any current from the circuit .

Question 26.

A 250-turn rectangular coil of length 2.1 cm and width 1.25 cm can carry a current of 85 μA and subjected to magnetic field of strength 0.85 T. Work done for rotating the coil by 180° against the torque is

[4 Marks]
  • (A) 4.55 μJ
  • (B) 1.15 μJ
  • (C) 2.3 μJ
  • (D) 9.1 μJ
Explanation:

Work done,

W = MB(cosθ₁ − cosθ₂)

When it is rotated by angle 180°

W = MB(cos0° − cos180°) = MB(1 + 1)

W = 2MIA

W =2(NIA) B

= 2 × 250 × 85 × 10⁻⁶ (1.25 × 2.1 × 10⁻⁴) × 85 × 10⁻²

≈ 9.1 μJ

Question 27.

An arrangement of three parallel straight wires placed perpendicular to plane of paper carrying same current I along the same direction is shown in fig. Magnitude of force per unit length on the middle wire 'B' is given by

[4 Marks] Diagram 10 – NEET-UG 2017 Question Paper Solutions
  • (A) μ₀i²/√2πd
  • (B) μ₀i²/2πd
  • (C) √2μ₀i ²/πd
  • (D) 2μ₀i²/πd
Explanation:

Force per unit length between two parallel current carrying conductors,

F = μ₀i₁i₂/2πd

Since same current flowing through both the wires

i₁ = i₂ = i

so F₁ = μ₀i²/2πd = F₂

∴ Magnitude of force per unit length on the middle wire 'B'

F_net = √(F₁² + F₂²)

= μ₀i²/√2πd

Diagram 11 – NEET-UG 2017 Question Paper Solutions
Question 28.

If θ₁ and θ₂ be the apparent angles of dip observed in two vertical planes at right angles to each other, then true angle of dip θ is given by :


[4 Marks]
  • (A) tan²θ = tan²θ₁ + tan²θ₂
  • (B) cot²θ = cot²θ₁ − cot²θ₂
  • (C) tan²θ = tan²θ₁ − tan²θ₂
  • (D) cot²θ = cot²θ₁ + cot²θ₂
Explanation:

If θ₁ and θ₂ are apparent angles of dip
Let α be the angle which one of the plane make with the magnetic meridian.
tan θ₁ = V/(H cos α)
i.e.,
cos α = V/(H tan θ₁) ...(i)

tan θ₂ = V/(H sin α)

i.e.,

sin α = V/(H tan θ₂) ...(ii)

Squaring and adding (i) and (ii), we get

cos² α + sin² α = (V/H)² (1/tan² θ₁ + 1/tan² θ₂)

i.e.,

1 = V²/H² [cot² θ₁ + cot² θ₂]

or

H²/V² = cot² θ₁ + cot² θ₂

i.e.,

cot² θ = cot² θ₁ + cot² θ₂

Question 29.

A long solenoid of diameter 0.1 m has 2 x 10⁴ turns per meter. At the centre of the solenoid, a coil of 100 turns and radius 0.01 m is placed with its axis coinciding with the solenoid axis. The current in the solenoid reduces at a constant rate to OA from 4 A in 0.05 s. If the resistance of the coil is 10π²Ω. the total charge flowing through the coil during this time is :

[4 Marks]
  • (A) 16πμC
  • (B) 32πμC
  • (C) 32μC
  • (D) 16μC
Explanation:

Given, no. of turns N = 100
radius, r = 0.01 m
resistance, R = 10π² Ω, n = 2 × 10⁴

As we know,

ε = −N dϕ/dt

⇒ ε/R = −N/R dϕ/dt

ΔI = −N/R dϕ/dt
= Δq/Δt


= −N/R Δϕ/Δt

Δq = −[N/R(Δϕ/Δt)] Δt

'−' ve sign shows that induced emf opposes the change of flux.

Δq = [μ₀nNπr²(Δi/Δt)] (1/R) Δt
= μ₀nNπr²Δi/R

Δq = (4π × 10⁻⁷) × 100 × 4 × π × (0.01)² × 2 × 10⁴/
10π ²
Δq = 32 μC

Question 30.

Figure shows a circuit that contains three identical resistors with resistance R = 9.0 Ω each, two identical inductors with inductance L = 2.0 mH each, and an ideal battery with emf ε = 18 V. The current ‘i’ through the battery just after the switch closed is

[4 Marks] Diagram 12 – NEET-UG 2017 Question Paper Solutions
  • (A) 2A
  • (B) 0.2A
  • (C) 2mA
  • (D) 0
Explanation:

At t = 0, no current flows through R₁ and R₃.

Current through battery just after the switch closed is

i =ε/ R₂ = 18/9 = 2 A

Diagram 13 – NEET-UG 2017 Question Paper Solutions
Question 31.

In an electromagnetic wave in free space the root mean square value of the electric field is Eₘₛ = 6 V/m. The peak value of the magnetic field is

[4 Marks]
  • (A) 1.41 × 10⁻⁸ T
  • (B) 2.83 × 10⁻⁸ T
  • (C) 4.23 × 10⁻⁸ T
  • (D) 0.70 × 10⁻⁸ T
Explanation:

Given, Eₘₛ = 6 V/m
Eₘₛ/Bₘₛ = c

⇒ Bᵣₘₛ = Eᵣₘₛ/c ...(i)
Bᵣₘₛ = B₀/√2⇒ B₀ = √2 Bᵣₘₛ
B₀ = √2 × Eᵣₘₛ/c From
equation (i)
= √2 × 6/3 × 10⁸
= 2.83 × 10⁻⁸ T

Question 32.

A beam of light from a source L is incident normally on a plane mirror fixed at a certain distance x from the source. The beam is reflected back and a spot on a scale placed just above the source I. When the mirror is rotated through a small angle θ, the spot of the light is found to move through a distance y on the scale. The angle θ is given by

[4 Marks]
  • (A) y/x
  • (B) x/2y
  • (C) x/y
  • (D) y /2x
Explanation:

When mirror is rotated by angle θ reflected ray will be rotated by 2θ.
According to the condition,
y/ x = 2θ
⇒ θ = y/2x

Diagram 14 – NEET-UG 2017 Question Paper Solutions
Question 33.

A thin prism having refracting angle 10° is made of glass of refractive index 1.42. This prism is combined with another thin prism of glass of refractive index 1.7. This combination produces dispersion without deviation. The refracting angle of second prism should be

[4 Marks]
  • (A) 10°
  • (B) 8°
  • (C) 6°
  • (D) 4°
Explanation:

For dispersion without deviation

(μ − 1)A₁ + (μ′ − 1)A₂ = 0

|(μ − 1)A₁| = |(μ′ − 1)A₂|

(1.42 − 1) × 10° = (1.7 − 1)A₂

4.2 = 0.7A₂

A₂ = 6°

Question 34.

Young's double slit experiment is first performed in air and then in a medium other than air. It is found that 8th bright fringe is observed where 5th dark fringe lies in air. The refractive index of the medium is nearly

[4 Marks]
  • (A) 1.69
  • (B) 1.25
  • (C) 1.78
  • (D) 1.59
Explanation:

According to question

8ᵀʰ bright fringe in medium = 5ᵀʰ dark fringe in air

Y₈ₜₕ bright = 8 (λD/μd)

Y₅ₜₕ dark = (2 × 5 − 1) λD/2d = 9λD/2d

⇒ 9 /2 (λD/d ) = 8 (λD/μd)

or, refractive index

μ = 16/9 = 1.78

Question 35.

Two Polaroids P₁ and P₂ are placed with their axis perpendicular to each other. Unpolarized light I₀ is incident on P₁. A third polaroid P₃ is kept in between P₁ and P₂ such that its axis makes an angle 45° with that of P₁. The intensity of transmitted light P₂ is

[4 Marks]
  • (A) I₀/16
  • (B) I₀/8
  • (C) I₀/4
  • (D) I₀/2
Explanation:

According to Malus law, I = I₀cos²θ

I₁ = I₀/2

I₂ = (I₀/2) cos²45°
= (I₀/2) × 1/2
= I₀/4

I₃ = (I₀/4) cos²45°
= I₀/8

Diagram 15 – NEET-UG 2017 Question Paper Solutions
Question 36.

The ratio of resolving powers of an optical microscope for two wavelengths λ₁ = 4000 Å and λ₂ = 6000 Å is

[4 Marks]
  • (A) 8 : 27
  • (B) 16 : 81
  • (C) 3 : 2
  • (D) 9 : 4
Explanation:

Resolving power of a microscope = 2μ sin θ/λ

i.e., R ∝ 1/λ, or R₁/R₂ = λ₂/λ₁

Given that the two wavelengths,

λ₁ = 4000 Å and λ₂ = 6000 Å

R₁/R₂ = 6000 Å /4000 Å = 3/2

Question 37.

The de-Broglie wavelength of a neutron in thermal equilibrium with heavy water at a temperature T (Kelvin)

and mass m, is :-

[4 Marks]
  • (A) 2h/√3mkT
  • (B) h/√ mkT
  • (C) 2h/√ mkT
  • (D) h/√3mkT
Explanation:

We know that, de-Broglie wavelength λ = h/√(2mKE)
K.E. of thermal neutron = 3/2 kT
λ = h/√ 2m (3/2 kT)
λ = h/√3mkT

Question 38.

The ratio of wavelengths of the last line of Balmer series and the last line of Lyman series is

[4 Marks]
  • (A) 0.5
  • (B) 1
  • (C) 2
  • (D) 4
Explanation:
For last line of Balmer series:
n₁ = 2 and n₂ = ∞
1/λB = RZ² [1/n₁² − 1/n₂²]

     = R₁² [1/2² − 1/∞²]
    1/λ_B   = 4/R   ...(i)

     
For last line of Lyman series:
n₁ = 1 and n₂ = ∞
1/λ_L = RZ² [1/n₁² − 1/n₂²]
     = RZ² [1/1² − 1/∞²]
    
λ_L = 1/R                      ...(ii)
Dividing equation (i) by (ii)
λ_B/λ_L = (4/R)/(1/R)
Ratio of wavelengths is
λ_B/λ_ = 4
Question 39.

Radioactive material 'A' has decay constant λ and material 'B' has decay constant λ'. Initially they have same number of nuclei. After what time, the ratio of number of nuclei of material 'B' to that 'A' will be 1/e?

[4 Marks]
  • (A) 1/λ
  • (B) 1/9λ
  • (C) 1/8λ
  • (D) 1/7λ
Explanation:

Diagram 16 – NEET-UG 2017 Question Paper Solutions
Question 40.

Which one of the following represents forward bias diode?

[4 Marks]
  • (A) Diagram 17 – NEET-UG 2017 Question Paper Solutions
  • (B) Diagram 18 – NEET-UG 2017 Question Paper Solutions
  • (C) Diagram 19 – NEET-UG 2017 Question Paper Solutions
  • (D) Diagram 20 – NEET-UG 2017 Question Paper Solutions
Explanation:

In forward bias, V₁ > V₂ i.e., in figure (d) p-side is at higher potential w.r.t. n-side of p-n junction diode.

Diagram 21 – NEET-UG 2017 Question Paper Solutions
Question 41.

In a common emitter transistor amplifier the audio signal voltage across the collector is 3 V. The resistance of collector is 3 kΩ. If current gain is 100 and the base resistance is 2 kΩ, the voltage and power gain of the amplifier is

[4 Marks]
  • (A) 200 and 1000
  • (B) 20 and 2000
  • (C) 15 and 200
  • (D) 150 and 15000
Explanation:

Given, current gain β = 100, R_C = 3kΩ, R_b = 2kΩ

Voltage gain (A_v) = β R_C/R_b = 100 (3/2) = 150

Power gain = A_v β = 150 × 100 = 15000

Question 42.

The given electrical network is equivalent to :

[4 Marks] Diagram 22 – NEET-UG 2017 Question Paper Solutions
  • (A) NOT gate
  • (B) AND gate
  • (C) OR gate
  • (D) NOR gate
Explanation:

Y₁ = A̅ +  B̅

Y₂ = Y₁ + Y̅₁ = Y̅₁ = A + B

Y = Y̅₂ = A̅ +  B̅ i.e. NOR gate.

Diagram 23 – NEET-UG 2017 Question Paper Solutions
Question 43.

Which one is the wrong statement ?

[4 Marks]
  • (A) de-Broglie's wavelength is given by λ = h/mv where m = mass of the particle, v = group velocity of the particle.
  • (B) The energy of 2s orbital is less than the energy of 2p orbital in case of Hydrogen like atoms.
  • (C) The uncertainty principle is ΔE × Δt ≥ h/4π
  • (D) Half filled and fully filled orbitals have greater stability due to greater exchange energy, greater symmetry and more balanced arrangement.
Explanation:

For hydrogen like atoms energy of 2s orbital and 2p-orbital is equal.

Question 44.

The element Z = 114 has been discovered recently.
It will belong to which of the following family/group and electronic configuration?

[4 Marks]
  • (A) Halogen family, [Rn] 5f¹⁴ 6d¹⁰ 7s² 7p⁵
  • (B) Nitrogen family, [Rn] 5f¹⁴ 6d¹⁰ 7s² 7p ⁶
  • (C) Carbon family, [Rn] 5f¹⁴ 6d¹⁰ 7s² 7p²
  • (D) Oxygen family, [Rn] 5f¹⁴ 6d¹⁰ 7s² 7p⁴
Explanation:

After ₈₆Rn (Group 18), elements from atomic number 89 to 103 (actinoids) are in group 3 114 = 103 + 11. Thus, element with atomic number 114 will be in group (3 + 11) or group 14 (carbon family).

The outer shell configuration of group 14 is ns²np².

Hence, only option (a) is correct.

Question 45.

Which of the following pairs of compounds isoelectronic and isostructural?

[4 Marks]
  • (A) BeCl₂, XeF₂
  • (B) TeI₂, XeF₂
  • (C) IF ₃ , XeF₂
  • (D) IBr₂⁻, XeF₂
Explanation:

IBr₂⁻, XeF₂
Total number of valence electrons are equal in both the species and both the species exhibit linear shape.

Question 46.

The species, having bond angles of 120° is:

[4 Marks]
  • (A) PH₃
  • (B) NCI₃
  • (C) ClF₃
  • (D) BCl₃
Explanation:

BCl₃ is trigonal planar and hence the bond angle is 120°.

Diagram 24 – NEET-UG 2017 Question Paper Solutions
Question 47.

Which of the following pairs of species have the same bond order?

[4 Marks]
  • (A) CN⁻, CO
  • (B) O₂, NO⁺
  • (C) CO, NO
  • (D) N₂, O⁻₂
Explanation:

CN⁻ and CO have same no. of electrons and have same bond order equal to 3.

Question 48.

A gas is allowed to expand in a well insulated container against a constant external pressure of 2.5 atm from an initial volume of 2.50 L to a final volume of 4.50 L. The change in internal energy ΔU of the gas in joules will be:

[4 Marks]
  • (A) −500 J
  • (B) +505 J
  • (C) 1136.25 J
  • (D) −505 J
Explanation:

The system is in isolated state.

∴ For an adiabatic process, q = 0

ΔU = q + w

∴ ΔU = w

= −PΔV

= −2.5 atm × (4.5 − 2.5) L

= −2.5 × 2 L-atm.

= −5 × 101.3 J

= −506.5 J ≈ −505 J

Question 49.

For a given reaction, ΔH = 35.5 kJ mol⁻¹ and ΔS = 83.6 JK⁻¹ mol⁻¹. The reaction is spontaneous at:

(Assume that ΔH and ΔS do not vary with temperature)

[4 Marks]
  • (A) T > 425 K
  • (B) All temperatures
  • (C) T > 298 K
  • (D) T < 425 K
Explanation:

Given ΔH = 35.5 kJ mol⁻¹
ΔS = 83.6 J K⁻¹ mol⁻¹
∴ ΔG = ΔH − TΔS
For a reaction to be spontaneous, ΔG = −ve
i.e., ΔH < TΔS

∵ T > ΔH /ΔS = 35.5*10³ Jmol⁻¹/83.6Jk⁻¹

So, the given reaction will be spontaneous at
T > 425 K

Question 50.

The equilibrium constant of the following are:

N₂ + 3H₂ ⇌ 2NH₃ K₁
N₂ + O₂ ⇌ 2NO K₂

H₂ + 1/2 O₂ ⇌ H₂O K₃

[4 Marks] Diagram 25 – NEET-UG 2017 Question Paper Solutions
  • (A) K₂³K₃/K₁
  • (B) K₂K₃³/K₁
  • (C) K₁K₃³/K₂
  • (D) K₂K₃/K₁
Explanation:

Diagram 26 – NEET-UG 2017 Question Paper Solutions
Question 51.

A 20 litre container at 400 K contains CO₂(g) at pressure 0.4 atm and excess of SrO (neglect volume occupied by SrO). The volume of the container is now decreased by moving the movable piston tighter, with constant temperature. The maximum volume of the container, when pressure of CO₂ attains its maximum value, will be:
(Given that : SrCO₃(s) ⇌ SrO(s) + CO₂(g), KP = 1.6 atm)

[4 Marks]
  • (A) 5 litre
  • (B) 2 litre
  • (C) 4 litre
  • (D) 10 litre
Explanation:
Max. pressure of CO₂ = Pressure of CO₂ at equilibrium
SrCO₃(s) ⇌ SrO(s) + CO₂(g)
Kₚ = P_CO₂ = 1.6 atm = maximum pressure of CO₂.
volume of container at this stage,
V = nRT/P                                  ...(i)
Since container is sealed and reaction was not earlier at equilibrium,
n = PV/RT = (0.4 × 20)/(RT)                  ...(ii)
Put equation (ii) in equation (i)
V = [(0.4 × 20)/(RT)]RT / 1.6
V = 5 L
Question 52.

Concentration of the Ag⁺ ions in a saturated solution of Ag₂C₂O₄ is 2.2 × 10⁻⁴ mol L⁻¹. Solubility product of Ag₂C₂O₄ is:

[4 Marks]
  • (A) 2.66 × 10⁻¹²
  • (B) 2.42 × 10⁻ ⁸
  • (C) 4.5 × 10⁻¹¹
  • (D) 5.3 × 10⁻¹²
Explanation:

Diagram 27 – NEET-UG 2017 Question Paper Solutions
Question 53.

It is because of inability of np² electrons of the valence shell to participate in bonding that:

[4 Marks]
  • (A) Sn⁴⁺ is reducing while Pb⁴⁺ is oxidising
  • (B) Sn²⁺ is oxidising while Pb⁴⁺ is reducing
  • (C) Sn²⁺ and Pb²⁺ are both oxidising and reducing
  • (D) Sn²⁺ is reducing while Pb⁴⁺ is oxidising
Explanation:

Due to inert pair effect, Pb(II) is more stable than Pb(IV).
Sn(IV) is more stable than Sn(II).

Pb(IV) is easily reduced to Pb(II) and can acts as an oxidising agent whereas Sn(II) is easily oxidised to Sn(IV) and can acts as a reducing agent.

Question 54.

The IUPAC name of the compound is:

[4 Marks] Diagram 28 – NEET-UG 2017 Question Paper Solutions
  • (A) 3-keto-2-methylhex-4-enal
  • (B) 3-keto-2-methylhex-5-enal
  • (C) 5-methyl-4-oxohex-2-en-5-al
  • (D) 5-formylhex-2-en-3-one
Explanation:

3-keto-2-methylhex-4-enal
Aldehydes get higher priority over ketone and alkene in numbering of principal carbon chain.

Diagram 29 – NEET-UG 2017 Question Paper Solutions
Question 55.

The most suitable method of separation of 1 : 1 mixture of ortho and para-nitrophenols is:

[4 Marks]
  • (A) Sublimation
  • (B) Steam distillation
  • (C) Crystallisation
  • (D) Chromatography
Explanation:

The o-isomer is steam volatile due to intra-molecular H-bonding. The p-isomer is not steam volatile due to intermolecular H-bonding or association of molecules.

Thus, both can be separated by steam distillation.

Question 56.

The correct statement regarding electrophile is:

[4 Marks]
  • (A) Electrophile is a negatively charged species and can form a bond by accepting a pair of electrons from another electrophile
  • (B) Electrophiles are generally neutral species and can form a bond by accepting pair of electrons from a nucleophile
  • (C) Electrophile is a negatively charged species and can form a bond by accepting a pair of electrons from a nucleophile
  • (D) Electrophile can be either neutral or positively charged species and can form a bond by accepting a pair of electrons from a nucleophile
Explanation:

Electrophile is a electron deficient species and can accept pair of electrons from nucleophile.

Question 57.

With respect to the conformers of ethane, which of the following statements is true?

[4 Marks]
  • (A) Bond angle remains same but bond length changes
  • (B) Both bond angles and bond length remains same
  • (C) Both bond angle and bond length change
  • (D) Bond angle changes but bond length remains same
Explanation:

There is no change in bond angles and bond lengths in the conformation of ethane.

Question 58.

Which one is the correct order of acidity?

[4 Marks]
  • (A) CH₃-CH₃>CH₂=CH₂>CH₃–C≡CH>CH≡CH
  • (B) CH≡CH>CH₂=CH₂>CH₃–C≡CH>CH₃–CH₃
  • (C) CH≡CH > CH₃–C≡CH > CH₂=CH₂ > CH₃–CH₃
  • (D) CH₂=CH₂>CH₃-CH=CH–>CH₃-c ≡CH>CH≡CH
Explanation:

Correct order is

H-C≡C -H > H₃c – C ≡ C-H > H₂c
(Two acidine hydrogensc) (One acidichydrogen)

= CH₂> CH₃ - CH₃

Question 59.

Which of the following is a sink for CO?

[4 Marks]
  • (A) Oceans
  • (B) Haemoglobin
  • (C) Plants
  • (D) Microorganism present in the soil
Explanation:

Microorganisms present in the soil is a sink for CO.

Question 60.

If molality of the dilute solutions is doubled, the value of molal depression constant (K_f) will be-

[4 Marks]
  • (A) tripled
  • (B) halved
  • (C) unchanged
  • (D) doubled
Explanation:

K_f (molal depression constant) only depends on the nature of the solvent and is independent of the Concentration of the solution.

Question 61.

Which of the following is dependent on temperature?

[4 Marks]
  • (A) Molality
  • (B) Weight percentage
  • (C) Mole fraction
  • (D) Molarity
Explanation:

Molarity depends on the volume of a solution which can be changed with change in temperature.

Question 62.

Ionic mobility of which of the following alkali metal ions is lowest when aqueous solution of their salts are put under an electric field?

[4 Marks]
  • (A) K
  • (B) Li
  • (C) Rb
  • (D) Na
Explanation:

Li⁺ being smallest, has maximum charge density.
∴ Li⁺ is most heavily hydrated among all alkali metal ions. Effective size of Li⁺ in aqueous solution is therefore, largest. So, moves slowest under electric field.

Question 63.

In the electrochemical cell:-
Zn | ZnSO₄ (0.01 M) || CuSO₄ (1.0 M) | Cu, the emf of this Daniell cell is E₁. When the concentration of ZnSO₄ is changed to 1.0 M and that of CuSO₄ changed to 0.01 M, the emf changes to E₂. From the following, which one is the relationship between E₁ and E₂? (Given, RT/F = 0.059)

[4 Marks]
  • (A) E₁ < E₂
  • (B) E₁ > E₂
  • (C) E₁ = E₂
  • (D) E₂ = 0 ≠ E₁
Explanation:

For cell,
Zn | ZnSO₄ (0.01 M) || CuSO₄ (1.0 M) | Cu

Ecell = E°cell − (2.303RT/ /nF log ([Zn²⁺] / [Cu²⁺]

∴ E₁ = E°cell − (2.303RT/2F) log(0.01/0.1)

When concentrations are changed for ZnSO₄ and CuSO₄, we can write

E₂ = E°cell − (2.303RT/2F)
* log(1/0.01)

∴ E₁ > E₂

Question 64.

Mechanism of a hypothetical reaction
X₂ + Y₂ → 2XY is given below:

(i) X₂ → X + X (fast)
(ii) X + Y₂ ⇌ XY + Y (slow)
(iii) X + Y → XY (fast)
The overall order of the reaction will be:

[4 Marks]
  • (A) 1.5
  • (B) 1
  • (C) 2
  • (D) 0
Explanation:
Overall rate = k[X][Y₂]      ...(1)
k = rate constant
Assuming step (i) to be reversible, its equilibrium constant,
k(eq)subscript = [X]²/[X₂]
⇒[X]² = k(eq)subscript [X₂]
⇒[X] = k(eq)subscript ½[X₂]½     ...(2)
From (eq)subscript  (1) and (2)
Rate = kk(eq)subscript ½[X₂]½[Y₂]
Overall order = 1/2 + 1 = 3/2 = 1.5
Question 65.

A first order reaction has a specific reaction rate of 10⁻² s⁻¹. How much time will it take for 20 g of the reactant to reduce to 5 g?

[4 Marks]
  • (A) 138.6 sec
  • (B) 346.5 sec
  • (C) 693.0 sec
  • (D) 238.6 sec
Explanation:

Half life for a first order reaction,
t₁/₂ = 0.693/K
So,
t₁/₂ = 0.693/10⁻² sec
Also, for the reduction of 20 g of reactant to 5 g, two half lives will be required.
∴ For 20 g of the reactant to reduce to 5 g, time taken,
t = 2 × (0.693/10⁻²) sec = 138.6 sec.

Question 66.

Which one of the following statements is not correct?

[4 Marks]
  • (A) The value of equilibrium constant is changed in the presence of a catalyst in the reaction at equilibrium
  • (B) Enzymes catalyse mainly bio-chemical reactions
  • (C) Catalyst does not initiate any reaction
  • (D) Coenzymes increase the catalytic activity of enzyme
Explanation:

A catalyst speeds up both forward and backward reaction with the same rate.
So, equilibrium constant is not affected by the presence of a catalyst at any given temperature.

Question 67.

Extraction of gold and silver involves leaching with CN⁻ ion. Silver is later recovered by

[4 Marks]
  • (A) distillation
  • (B) zone refining
  • (C) displacement with Zn
  • (D) liquation
Explanation:

Zn being more reactive than Ag and Au, displaces them.

Question 68.

In which pair of ions both the species contain S–S bond?

[4 Marks]
  • (A) S₄O₆²⁻, S₂O₇²⁻
  • (B) S₂O₇²⁻, S₂O₈²⁻
  • (C) S₄O₆²⁻, S₂O₃²⁻
  • (D) S₂O₇²⁻, S₂O₃²⁻
Explanation:

Zn being more reactive than Ag and Au, displaces them.

Diagram 30 – NEET-UG 2017 Question Paper Solutions
Question 69.

Name the gas that can readily decolourise acidified KMnO₄ solution :

[4 Marks]
  • (A) NO₂
  • (B) CO₂
  • (C) SO₂
  • (D) P₂O₅
Explanation:

Potassium permanganate has a purple colour. When sulphur dioxide reacts with potassium permanganate, the solution decolourises.

5SO₂ + 2KMnO₄ + 2H₂O → 2H₂SO₄ + 2MnSO₄ + K₂SO₄

Question 70.

The reason for greater range of oxidation states in actinoids is attributed to :

[4 Marks]
  • (A) actinoid contraction
  • (B) 5f, 6d and 7s levels having comparable energies
  • (C) 4f and 5d levels being close in energies
  • (D) the radioactive nature of actinoids
Explanation:

Minimum comparable energy gap between 5f, 6d and 7s subshell makes electron excitation easier, hence there is a greater range of oxidation states in actinoids.

Question 71.

The correct order of the stoichiometries of AgCl formed when AgNO₃ in excess is treated with the complexes CoCl₃·6NH₃, CoCl₃·5NH₃, CoCl₃·4NH₃ respectively is :

[4 Marks]
  • (A) 3AgCl, 1AgCl, 2AgCl
  • (B) 3AgCl, 2AgCl, 1AgCl
  • (C) 2AgCl, 3AgCl ,1AgCl,
  • (D) 1AgCl, 3AgCl, 2AgCl
Explanation:

In the given complex, the CN of Co is 6, and the complex has octahedral geometry.

Diagram 31 – NEET-UG 2017 Question Paper Solutions
Question 72.

HgCl₂ and I₂ both when dissolved in water containing I⁻ ions, the pair of species formed is :

[4 Marks]
  • (A) HgI₄²⁻, I₃⁻
  • (B) HgI₂, I⁻
  • (C) HgI₂, I₃⁻
  • (D) Hg₂I₂, I⁻
Explanation:

In a solution containing HgCl₂, I₂ and I⁻, both HgCl₂ and I₂ compete for I⁻.

Since formation constant of [HgI₄]²⁻ is very large (1.9 × 10³⁰) as compared with I₃⁻ (Kf = 700).

∴ I⁻ will preferentially combine with HgCl₂.

HgCl₂ + 2I⁻ → HgI₂ (Red ppt ) ↓ + 2Cl⁻

HgI₂ + 2I⁻ → [HgI₄]²⁻ soluble

Question 73.

Correct increasing order for the wavelengths of absorption in the visible region the complexes of Co³⁺ is :-

[4 Marks]
  • (A) [Co(en)₃]³⁺, [Co(NH₃)₆]³⁺, [Co(H₂O)₆]³⁺
  • (B) [Co(NH₃)₆]³⁺, [Co(en)₃]³⁺, [Co(H₂O)₆]³⁺
  • (C) [Co(H₂O)₆]³⁺, [Co(en)₃]³⁺, [Co(NH₃)₆]³⁺
  • (D) [Co(H₂O)₆]³⁺, [Co(NH₃)₆]³⁺, [Co(en)₃]³⁺
Explanation:

The order of strength of ligand is

en > NH₃ > H₂O

For stronger ligand, the value of Δ₀ for the complex is higher.

Hence, the increasing order of wavelengths of absorption is:

[Co(en)₃]³⁺ < [Co(NH₃)₆]³⁺ < [Co(H₂O)₆]³⁺

Question 74.

Pick out the correct statement with respect to [Mn(CN)₆]³⁻ :-

[4 Marks]
  • (A) It is sp³d² hybridised and tetrahedral
  • (B) It is sp³d² hybridised and octahedral
  • (C) It is d²sp³ hybridised and octahedral
  • (D) It is dsp² hybridised and square planar
Explanation:

Diagram 32 – NEET-UG 2017 Question Paper Solutions
Question 75.

An example of sigma bonded organometallic compound is :

[4 Marks]
  • (A) Ruthenocene
  • (B) Cobaltocene
  • (C) Ferrocene
  • (D) Grignard's reagent
Explanation:

Grignard's reagent (RMgX) is a σ-bonded organometallic compound.

Question 76.

Which one is the most acidic compound ?

[4 Marks]
  • (A) Diagram 33 – NEET-UG 2017 Question Paper Solutions
  • (B) Diagram 34 – NEET-UG 2017 Question Paper Solutions
  • (C) Diagram 35 – NEET-UG 2017 Question Paper Solutions
  • (D) Diagram 36 – NEET-UG 2017 Question Paper Solutions
Explanation:

Electron withdrawing –NO₂ group has very strong –I and –R effects so, compound 3 will be most acidic

Question 77.

The heating of phenyl-methyl ethers with HI produces

[4 Marks]
  • (A) Iodobenzene
  • (B) Phenol
  • (C) Benzene
  • (D) Ethyl chlorides
Explanation:

When Ar–O–R ethers are reacted with HI, they are cleaved at weaker O–R bond to give phenol and alkyl iodide.

Diagram 37 – NEET-UG 2017 Question Paper Solutions
Question 78.

Consider the reactions :-

Identify A, X, Y and Z

[4 Marks] Diagram 38 – NEET-UG 2017 Question Paper Solutions
  • (A) A–Methoxymethane, X–Ethanoic acid, Y–Acetate ion, Z–Hydrazine.
  • (B) A–Ethanal, X–Ethanol, Y–But-2-enal, Z–Semicarbazone.
  • (C) A–Ethanol, X–Acetaldehyde, Y–Butanone, Z–Hydrazone.
  • (D) A–Methoxymethane, X–Ethanol, Y–Ethanoic acid, Z–Semicarbazide.
Explanation:

Since 'A' gives positive silver mirror test therefore, it must be an aldehyde or α-Hydroxyketone. Also, reaction with OH⁻ i.e., aldol condensation (by assuming alkali to be dilute) indicates that 'A' is aldehyde as aldol reaction of ketone is reversible and carried out in special apparatus. It indicates that 'A' is an aldehyde.

Diagram 39 – NEET-UG 2017 Question Paper Solutions
Question 79.

The correct increasing order of basic strength for the following compounds is :

[4 Marks] Diagram 40 – NEET-UG 2017 Question Paper Solutions
  • (A) lll
  • (B) lll
  • (C) ll
  • (D) ll
Explanation:

–NO₂ group has strong –R effect and –CH₃ shows +R effect.

∴ Order of basic strength is

Diagram 41 – NEET-UG 2017 Question Paper Solutions
Question 80.

Which of the following reactions is appropriate for converting acetamide to methanamine?

[4 Marks]
  • (A) Gabriel's phthalimide synthesis
  • (B) Carbylamine reaction
  • (C) Stephens reaction
  • (D) Hoffmann hypobromamide reaction
Explanation:

It is called Hoffmann Bromamide reaction.

Diagram 42 – NEET-UG 2017 Question Paper Solutions
Question 81.

Which of the following statements is not correct :

[4 Marks]
  • (A) Ovalbumin is a simple food reserve in egg-white
  • (B) Blood proteins thrombin and fibrinogen are involved in blood clotting
  • (C) Denaturation makes the proteins more active
  • (D) Insulin maintains sugar level in the blood of human body
Explanation:

Due to denaturation of proteins, helix get uncoiled and protein loses its biological activity.

Question 82.

Mixture of chloroxylenol and terpineol acts as:


[4 Marks]
  • (A) analgesic
  • (B) antibiotic
  • (C) antiseptic
  • (D) antipyretic
Explanation:

Dettol is a mixture of chloroxylenol and terpineol which is a very commonly known antiseptic.

Question 83.

The heating of phenyl-methyl ethers with HI produces

[4 Marks]
  • (A) Ethyl chlorides
  • (B) Phenol
  • (C) Benzene
  • (D) Iodobenzene
Explanation:

When Ar–O–R ethers are reacted with HI, they are cleaved at weaker O–R bond to give phenol and alkyl iodide.

Diagram 43 – NEET-UG 2017 Question Paper Solutions
Question 84.

Which of the following are found in extreme saline conditions?

[4 Marks]
  • (A) Archaebacteria
  • (B) Mycobacteria
  • (C) Cyanobacteria
  • (D) Eubacteria
Explanation:

Archaebacteria are able to survive in harsh conditions due to the presence of branched lipid chain in cell membrane that reduces fluidity of cell membrane. It includes halophiles which are exclusively found in saline habitats.

Question 85.

Which of the following components provides sticky character to the bacterial cell?

[4 Marks]
  • (A) Plasma membrane
  • (B) Cell wall
  • (C) Glycocalyx
  • (D) Nuclear membrane
Explanation:

Sticky character of the bacterial wall is due to glycocalyx which is rich in glycoproteins.

Question 86.

Which among the following are the smallest living cells, known without a definite cell wall, pathogenic to plants as well as animals and can survive without oxygen?

[4 Marks]
  • (A) Nostoc
  • (B) Bacillus
  • (C) Pseudomonas
  • (D) Mycoplasma
Explanation:

Mycoplasmas are smallest, prokaryotes lacking cell wall and are pleomorphic in nature. These are pathogenic to both plants and animals.

Question 87.

Viroids differ from viruses in having:

[4 Marks]
  • (A) RNA molecules without protein coat
  • (B) DNA molecules with protein coat
  • (C) RNA molecules with protein coat
  • (D) DNA molecules without protein coat
Explanation:

Viroids in nature are sub-viral agents as infectious

RNA particles, without protein coat.

Question 88.

An example of colonial alga is:

[4 Marks]
  • (A) Spirogyra
  • (B) Chlorella
  • (C) Ulothrix
  • (D) Volvox
Explanation:

Volvox is a motile colonial fresh water green alga. It forms spherical colonies. It was first observed with a light microscope by Van Leeuwenhoek (1700) within the volvocales.

Question 89.

Zygotic meiosis is characteristic of:

[4 Marks]
  • (A) Fucus
  • (B) Funaria
  • (C) Chlamydomonas
  • (D) Marchantia
Explanation:

Chlamydomonas has haplontic life cycle hence shows

zygotic meiosis.

Question 90.

Life cycle of Ectocarpus and Fucus respectively are:

[4 Marks]
  • (A) Diplontic, Haplodiplontic
  • (B) Haplodiplontic, Haplontic
  • (C) Haplodiplontic, Diplontic
  • (D) Haplontic, Diplontic
Explanation:

Ectocarpus exhibits haplodiplontic life cycle while

Fucus has diplontic life cycle

Question 91.

Select the mismatch

[4 Marks]
  • (A) Cycas - Dioecious
  • (B) Salvinia — Heterosporous
  • (C) Pinus — Dioecious
  • (D) Equisetum - Homosporous
Explanation:

Pinus is monoecious plant comprising of both male and female cones on same plant.

Question 92.

Double fertilization is exhibited by :

[4 Marks]
  • (A) Gymnosperms
  • (B) Fungi
  • (C) Algae
  • (D) Angiosperms
Explanation:

Double fertilisation is a unique feature exhibited only by angiosperms. It involves both syngamy and triple fusion.

Question 93.

In case of poriferans, the spongocoel is lined with flagellated cells called:

[4 Marks]
  • (A) oscula
  • (B) choanocytes
  • (C) mesenchymal cells
  • (D) ostia
Explanation:

In poriferans (sponges) choanocytes (collar cells)

form lining of spongocoel. Flagella present in collar cells

provide circulation to water in water canal system.

Question 94.

An important characteristic that Hemichordates share with

Chordates is

[4 Marks]
  • (A) Absence of notochord
  • (B) Pharynx without gill slits
  • (C) Pharynx with gill slits
  • (D) Ventral tubular nerve cord
Explanation:

Pharyngeal gflI slns are present in hemlchordates and in chordates. Notochord is present in chordates only. Ventral tubular nerve cord is present in non-chordates.

Question 95.

Which among these is the correct combination of aquatic

mammals?

[4 Marks]
  • (A) Seals, Dolphins, Sharks
  • (B) Trygon, Whales, Seals
  • (C) Whales, Dolphins, Seals
  • (D) Dolphins, Seals, Trygon
Explanation:

Sharks and Trygon (sting ray) are the members of cartilag- inous fish while Whale, Dolphin and Seals are aquatic mammals belong to class mammalia.

Question 96.

Plants which produce characteristic pneumatophores and show

vivipary belong to:

[4 Marks]
  • (A) Halophytes
  • (B) Psammophytes
  • (C) Mesophytes
  • (D) Hydrophytes
Explanation:

Halophytes growing in saline soils show vivipary:

seed germination and have pneumatophores for gaseq

exchange.

Question 97.

In Bougainvillea thoms are the modifications of

[4 Marks]
  • (A) Stipules
  • (B) Leaf
  • (C) Stem
  • (D) Adventitious root
Explanation:

Thorns are hard, pointed straight structures for protection against grazing animal. These are modified stem.

Question 98.

Coconut fruit is a:

[4 Marks]
  • (A) Drupe
  • (B) Nut
  • (C) Capsule
  • (D) Bemry
Explanation:

Coconut fruit is a drupe . A drupe is a fleshy fruit with thin skin and central stone containing the seed

Question 99.

The morphological nature of the edible part of coconut is;

[4 Marks]
  • (A) Perisperm
  • (B) Pericarp
  • (C) Cotyledon
  • (D) Endosperm
Explanation:

The edible part of coconut is its endosperm. Coconut has double endosperm, liquid endosperm and cellular.

Question 100.

Root hairs develop from the region of

[4 Marks]
  • (A) root cap
  • (B) Elongation
  • (C) Meristematic activity
  • (D) Maturation
Explanation:

In roots, the root hairs develops from zone of mat ration. This zone is differentiated zone thus bearing hairs.

Question 101.

‘Which of the following is made up of dead cells?

[4 Marks]
  • (A) Xylem parenchyma
  • (B) Phloem
  • (C) Collenchyma
  • (D) Phellem
Explanation:

Cork cambium undergoes periclinal division and Cuts off thick walled suberised dead cells towards outside i.e phellem (cork) and it cuts off thin walled living cells i.e., phelloderm inner side.

Question 102.

Which of the following facilitates opening of stomatal aperture?

[4 Marks]
  • (A) Decrease in turgidity of guard cells
  • (B) Radial orientation of cellulose micro-fibrils in the cell wall of guard cells
  • (C) Longitudinal orientation of cellulose microfibrils in the cell wall of guard cells
  • (D) Contraction of outer wall of guard cells
Explanation:

Cellulose microfibrils are arranged radially rather than longitudinally which makes easy for the stomata to open.

Question 103.

The vascular cambium normally gives rise to :

[4 Marks]
  • (A) Primary phloem
  • (B) Secondary xylem
  • (C) Periderm
  • (D) Phelloderm
Explanation:

During secondary growth in plants vascular cambium gives rise to secondary xylem and secondary phloem. Phelloderm is formed by cork cambium. Periderm is the corky outer layer formed in secondary thickening.

Question 104.

Frog’s heart when taken out of the body continues to beat for sometime.Select the best option from the following statements.

(A) Frog is a poikilotherm.

(B) Frog does not have any coronary circulation.

(C) Heart is “myogenic” in nature.

(D) Heart is autoexcitable

[4 Marks]
  • (A) (C) and (D)
  • (B) Only (c)
  • (C) Only (D)
  • (D) (A) and (B)
Explanation:

The vertebrates process myogenic heart which is self contractile system or auto excitable; it will thus keep working outside the body for some time.

Question 105.

which of the following cell organelles is responsible for extracting energy from carbohydrates to form ATP?

[4 Marks]
  • (A) Lysosome
  • (B) Chloroplast
  • (C) Mitochondrion
  • (D) Ribosome
Explanation:

The site of aerobic oxidation of carbohydrates in cells to generate ATP are mitochondria.

Question 106.

About 98 percent of the mass of every living organism is composed of just six elements including carbon, hydrogen, nitrogen, oxygen and

[4 Marks]
  • (A) magnesium and sodium
  • (B) sulphur and magnesium
  • (C) calcium and phosphorus
  • (D) phosphorus and sulphur
Explanation:

Calcium and phosphorus are the remaining elements.

Question 107.

Which one of the following statements is correct, with reference to enzymes?

[4 Marks]
  • (A) Holoenzyme = Apoenzyme + Coenzyme
  • (B) Coenzyme = Apoenzyme + Holoenzyme
  • (C) Apoenzyme = Holoenzyme + Coenzyme
  • (D) Holoenzyme = Coenzyme + Co-factor
Explanation:

Holoenzyme is conjugated enzyme which consists of a protein part called apoenzyme and a non-protein called cofactor. Coenzyme are also organic compounds but their association with apoenzyme is only transient and acts as cofactors.

Question 108.

Which of the following options gives the correct sequence of events during mitosis?

[4 Marks]
  • (A) Condensation → nuclear membrane disassembly → arrangement at equator → centromere division → segregation → telophase
  • (B) Condensation → crossing over → nuclear membrane disassembly → segregation → telophase
  • (C) Condensation → arrangement at equator → centromere division → segregation → telophase
  • (D) Condensation → nuclear membrane disassembly → crossing over → segregation → telophase
Explanation:

The correct sequence of events occurred during mitosis would be as follows:

(i) DNA condensation occurs so that chromosomes become visible during early to mid-prophase.
(ii) Disassembly of nuclear membrane begins at late prophase or transition to metaphase.
(iii) Chromosomes align at equator during metaphase.
(iv) Centromere division occurs during anaphase forming daughter chromosomes.
(v) During anaphase segregation also occurs in which daughter chromosomes separate and move to opposite poles.
(vi) Telophase finally leads to formation of two daughter nuclei.

Question 109.

Which of the following are not polymeric?

[4 Marks]
  • (A) Nucleic acids
  • (B) Lipids
  • (C) Polysaccharides
  • (D) Proteins
Explanation:

– Nucleic acids are polymers of nucleotides.
– Proteins are polymers of amino acids.
– Polysaccharides are polymers of monosaccharides.
– Lipids are tri-esters of fatty acids with glycerol.


Question 110.

DNA replication in bacteria occurs


[4 Marks]
  • (A) Prior to fission
  • (B) During S phase
  • (C) Just before transcription
  • (D) Within nucleolus
Explanation:

In bacteria DNA replication occurs in cytoplasm prior to fission. Prokaryotes due to their primitive nature do not show well marked S-phase

Question 111.

Anaphase Promoting Complex (APC) is a protein degradation machinery necessary for proper mitosis of animal cells. If APC is defective in a human cell, which of the following is expected to occur?

[4 Marks]
  • (A) Chromosomes will not segregate
  • (B) Chromosomes will be fragmented
  • (C) Chromosomes will not condense
  • (D) Recombination of chromosome arms will occur
Explanation:

During anaphase, Anaphase Promoting Complex (APC) is a protein necessary for separation of daughter chromosomes. A defective APC will cause the chromosomes fail to segregate during anaphase.

Question 112.

The water potential of pure water is

[4 Marks]
  • (A) Less than zero
  • (B) More than zero but less than one
  • (C) More than one
  • (D) Zero
Explanation:

By convention, the water potential of pure water at standard temperature, which is not under any pressure, is taken to be zero. (Ψw = 0)

Question 113.

With reference to factors affecting the rate of photosynthesis, which of the following statements is not correct?

[4 Marks]
  • (A) Increasing atmospheric CO₂ concentration up to 0.05% can enhance CO₂ fixation rate
  • (B) C₃ plants respond to higher temperatures with enhanced photosynthesis while C₄ plants have much lower temperature optimum
  • (C) Tomato is a greenhouse crop which can be grown in CO₂-enriched atmosphere for higher yield
  • (D) Light saturation for CO₂ fixation occurs at 10% of full sunlight
Explanation:

In C₃ plants photosynthesis decreases at higher temperature due to increased photorespiration.

C₄ plants have higher temperature optimum because of the presence of enzyme called pyruvate phosphate dikinase, which is sensitive to low temperature.

Question 114.

Phosphoenol Pyruvate (PEP) is the primary CO₂ acceptor in:

[4 Marks]
  • (A) C₄ plants
  • (B) C₂ plants
  • (C) C₃ and C₄ plants
  • (D) C₃ plants
Explanation:

In the mesophyll cells cytoplasm of C₄ plants like sugarcane, maize, sorghum etc. PEP is 3C compound which serves as primary CO₂ acceptor.

Question 115.

Which statement is wrong for Kreb's cycle?

[4 Marks]
  • (A) During the conversion of succinyl CoA to succinic acid, a molecule of GTP is synthesised.
  • (B) There is one point in the cycle where FAD⁺ is reduced to FADH₂.
  • (C) There are three points in the cycle where NAD⁺ is reduced to NADH + H⁺.
  • (D) The cycle starts with condensation of acetyl group (acetyl CoA) with pyruvic acid to yield citric acid.
Explanation:

Krebs cycle begins with condensation of acetyl CoA (2C) with oxaloacetic acid (4C) to form citric acid (6C).

Question 116.

Fruit and leaf drop at early stages can be prevented by the application of

[4 Marks]
  • (A) Cytokinins
  • (B) Gibberellic acid
  • (C) Auxins
  • (D) Ethylene
Explanation:

Auxins helps to prevent premature leaf and fruit fall.

Question 117.

Which cells of "Crypts of Lieberkuhn" secrete antibacterial lysozyme?

[4 Marks]
  • (A) Paneth cells
  • (B) Zymogen cells
  • (C) Kupffer cells
  • (D) Argentaffin cells
Explanation:

– Kupffer-cells are phagocytic cells present in liver.
– Zymogen cells are enzyme producing cells which are secreted by pancreas.
– Paneth cell secrete lysozyme which acts as anti-bacterial agent, into the lumen of intestine.
– Argentaffin cells are hormone producing cells.

Question 118.

The hepatic portal vein drains blood to liver from:

[4 Marks]
  • (A) Kidneys
  • (B) Intestine
  • (C) Heart
  • (D) Stomach
Explanation:

In hepatic portal system, hepatic portal vein drains blood to liver from intestine.

Question 119.

A baby boy aged two years is admitted to play school and passes through a dental check-up. The dentist observed that the baby had twenty teeth. Which teeth were absent?

[4 Marks]
  • (A) Incisors
  • (B) Molars
  • (C) Pre-molars
  • (D) Canines
Explanation:

Total number of teeth in a human child is 20. In primary dentition premolars are absent.

Question 120.

Which of the following options best represents the enzyme composition of pancreatic juice?

[4 Marks]
  • (A) amylase, pepsin, trypsinogen, maltase
  • (B) peptidase, amylase, pepsin, rennin
  • (C) lipase, amylase, trypsinogen, procarboxypeptidase
  • (D) amylase, peptidase, trypsinogen, rennin
Explanation:

Rennin and Pepsin enzymes are present in the gastric juice whereas Maltase is present in the intestinal juice.

Question 121.

Lungs are made up of air-filled sacs, the alveoli. They do not collapse even after forceful expiration, because of:

[4 Marks]
  • (A) Inspiratory Reserve Volume
  • (B) Tidal Volume
  • (C) Residual Volume
  • (D) Expiratory Reserve Volume
Explanation:

Volume of air present in lungs after forceful expiration is residual volume prevents the collapsing of alveoli.

Question 122.

Adult human RBCs are enucleated. Which of the following statement(s) is/are most appropriate explanation for this feature?

(1) They do not need to reproduce
(2) They are somatic cells
(3) They do not metabolize
(4) All their internal space is available for oxygen transport

[4 Marks]
  • (A) only (1).
  • (B) only (4).
  • (C) (1), (3) and (4).
  • (D) (2) and (3).
Explanation:

In human RBCs, nucleus get degenerates during maturation and it provide more space for oxygen carrying pigment (haemoglobin). It lacks many cell organelles including mitochondria so respires anaerobically.

Question 123.

Which of the following statements is correct?

[4 Marks]
  • (A) The descending limb of loop of Henle is permeable to electrolytes.
  • (B) The ascending limb of loop of Henle is impermeable to water.
  • (C) The descending limb of loop of Henle is impermeable to water.
  • (D) The ascending limb of loop of Henle is permeable to water.
Explanation:

Descending limb of loop of Henle is permeable to swater but impermeable to electrolytes whereas ascending limb is impermeable to water but permeable to electrolytes.

Question 124.

The pivot joint between atlas and axis is a type of:

[4 Marks]
  • (A) Cartilaginous joint
  • (B) Synovial joint
  • (C) Fibrous joint
  • (D) Saddle joint
Explanation:

Pivot joint is a type of synovial joint which provide freely movement between atlas and axis vertebrae of vertebral column.

Question 125.

X' pairs of ribs in humans and 'Y' pairs are true ribs. Select the option that correctly represents values of X and Y and provides their explanation:

[4 Marks]
  • (A) X – 24, Y – 12 True ribs are dorsally attached to vertebral column but are free on ventral side.
  • (B) X – 12, Y – 5 True ribs are attached dorsally to vertebral column and sternum.
  • (C) X – 24, Y – 7 True ribs are dorsally attached to vertebral column but are free on ventral side
  • (D) X – 12, Y – 7 True ribs are attached dorsally to vertebral column and ventrally to the sternum.
Explanation:

In human, 12 pairs of ribs are present out of which 7 pairs of ribs 1st to 7th pair) are dorsally attached to vertebral column and ventrally to the sternum.

Question 126.

Myelin sheath is produced by:

[4 Marks]
  • (A) Oligodendrocytes and Osteoclasts
  • (B) Astrocytes and Schwann cells
  • (C) Schwann cells and Oligodendrocytes
  • (D) Osteoclasts and Astrocytes
Explanation:

Miyelin sheath wrapped around the nerve axon. Oligodendrocytes are neuroglial cells which produce myelin sheath in central nervous system while Schwann cell produces myelin sheath in peripheral nervous system.

Question 127.

Receptor sites for neurotransmitter are present on:

[4 Marks]
  • (A) Pre-synaptic membrane
  • (B) Tips of axons
  • (C) Post-synaptic membrane
  • (D) Membrane of synaptic vesicles
Explanation:

Pre-synaptic membrane is involved in the release of neurotransmitter in the chemical synapse. The receptors sites for neurotransmitters are present on post-synaptic membrane of neuron.

Question 128.

Good vision depends on adequate intake of carotene rich food.
Select the best option from the following statements:

(i) Vitamin A derivatives are formed from carotene
(ii) The photopigments are embedded in the membrane of the inner segment
(iii) Retinal is a derivative of Vitamin A
(iv) Retinal is a light absorbing part of all the visual photopigments

[4 Marks]
  • (A) (i) and (iv)
  • (B) (ii), (iii) and (iv)
  • (C) (i) and (iii)
  • (D) (i), (iii) and (iv)
Explanation:

Carotene is the source of retinal which is involved in formation of thodopsin of rod cells. Retinal, a derivative of vitamin A, is the light-absorbing part of all visual photopigments. Photopigments are occur entirely on the surface of membrane disc.

Question 129.

A decrease in blood pressure / volume will not cause the release of:

[4 Marks]
  • (A) Aldosterone
  • (B) Atrial natriuretic factor
  • (C) ADH
  • (D) Renin
Explanation:

A decrease in blood pressure / volume stimulates the release of renin, aldosterone, and ADH while increase in blood pressure / volume stimulates the release of Atrial Natriuretic Factor (ANF) secreted by atria of heart, which causes vasodilation and also inhibits RAAS (Renin Angiotensin Aldosterone System) mechanism that decreases the blood volume/pressure.

Question 130.

Attractants and rewards are required for:

[4 Marks]
  • (A) Entomophily
  • (B) Hydrophily
  • (C) Cleistogamy
  • (D) Anemophily
Explanation:

Insect pollinated plants provide rewards as edible pollen grain and nectar as usual rewards. In order to mate Hialize and maximize pollination flowers have developed a set of attributes which are aimed at attracting the pollinators called attractants.

Question 131.

Flowers which have single ovule in the ovary and are packed into inflorescence are usually pollinated by:

[4 Marks]
  • (A) Bat
  • (B) Water
  • (C) Bee
  • (D) Wind
Explanation:

Wind pollination or anemophily occurs in flowers which are having a single ovule in each ovary, and numerous flowers packed in an inflorescence. It is a non-directional pollination.

Question 132.

A dioecious flowering plant prevents both:

[4 Marks]
  • (A) Geitonogamy and xenogamy
  • (B) Autogamy and geitonogamy
  • (C) Autogamy and xenogamy
  • (D) Cleistogamy and xenogamy
Explanation:

Autogamy occurs in bisexual flowers. Geitonogamous flowers are unisexual but present in the same plant. Dioecious condition is observed when unisexual male and female flowers are present on different plants and it prevents both autogamy and geitonogamy.

Question 133.

Functional megaspore in an angiosperm develops into?

[4 Marks]
  • (A) Embryo
  • (B) Ovule
  • (C) Embryo sac
  • (D) Endosperm
Explanation:

The first cell of female gametophytic generation in angiosperm is megaspore. It undergoes three successive mitotic division to form 8-mucleated and 7-celled embryo sac.

Question 134.

Capacitation occurs in:

[4 Marks]
  • (A) Epididymis
  • (B) Female reproductive tract
  • (C) Rete testis
  • (D) Vas deferens
Explanation:

Capacitation is increase in fertilising capacity of sperms which occurs in female reproductive tract. It is required to render sperm to fertilize an oocyte.

Question 135.

The function of copper ions in copper releasing IUD's is:

[4 Marks]
  • (A) They inhibit ovulation
  • (B) They make uterus unsuitable for implantation
  • (C) They suppress sperm motility and fertilising capacity of sperms
  • (D) They inhibit gametogenesis
Explanation:

Cu²⁺interfere in the sperm movement, ‘which suppress the sperm motility and fertilising capacity of sperms.

Question 136.

In case of a couple where the male is having a very low sperm count, which technique will be suitable for fertilisation?

[4 Marks]
  • (A) Gamete intracytoplasmic fallopian transfer
  • (B) Artificial Insemination
  • (C) Intracytoplasmic sperm injection
  • (D) Intrauterine transfer
Explanation:

Infertility cases due to inability of the male partner to inseminate the female or due to very low sperm count in the ejaculates, could be corrected by using artificial insemination (AI) technique. In this procedure, semen is injected directly into the vagina or uterus.

Question 137.

The genotypes of husband and wife are IᴬIᴮ and Iᴬi. Among the blood types of their children, how many different genotypes and phenotypes are possible?

[5 Marks]
  • (A) 3 genotypes ; 4 phenotypes
  • (B) 4 genotypes ; 3 phenotypes
  • (C) 4 genotypes ; 4 phenotypes
  • (D) 3 genotypes ; 3 phenotypes
Explanation:

Diagram 44 – NEET-UG 2017 Question Paper Solutions
Question 138.

Among the following characters, which one was not considered by Mendel in his experiments on pea?

[4 Marks]
  • (A) Pod – Inflated or Constricted
  • (B) Pod – Inflated or Constricted
  • (C) Seed – Green or Yellow
  • (D) Trichomes – Glandular or non-glandular
Explanation:

During his experiments Mendel have taken seven characters in a pea plant. Among these, nature of trichomes i.e. glandular or non-glandular was not considered by Mendel.

Question 139.

Which one from those given below is the period for Mendel's hybridisation experiments?

[4 Marks]
  • (A) 1856 – 1863
  • (B) 1870 – 1877
  • (C) 1857 – 1869
  • (D) 1840 – 1850
Explanation:

According to NCERT, Mendel conducted hybridisation experiments for 7 years on Pea plant between 1856 to 1863 and his data was published in 1865.

Question 140.

Thalassemia and sickle cell anemia are caused due to a problem in globin molecule synthesis. Select the correct statement:

[4 Marks]
  • (A) Both are due to a qualitative defect in globin chain synthesis
  • (B) Sickle cell anemia is due to a quantitative problem of globin molecules
  • (C) Thalassemia is due to less synthesis of globin molecules
  • (D) Both are due to a quantitative defect in globin chain synthesis
Explanation:

Thalassemia is a quantitative problem of synthesising very few globin molecules while sickle cell anaemia is a qualitative problem of synthesising an incorrectly functioning globin.

Question 141.

A disease caused by an autosomal primary non-disjunction is:

[4 Marks]
  • (A) Turner's Syndrome
  • (B) Klinefelter's Syndrome
  • (C) Sickle Cell Anemia
  • (D) Down's Syndrome
Explanation:

Down’s syndrome is caused by non-disjunction of 21ˢᵗ chromosome i.e. Trisomy.

Question 142.

The final proof for DNA as the genetic material came from the experiments of:

[4 Marks]
  • (A) Griffith
  • (B) Avery, Macleod and McCarty
  • (C) Har Gobind Khorana
  • (D) Hershey and Chase
Explanation:

Hershey and Chase proved that DNA as genetic material. They used bacteriophage for their experimental.

Question 143.

DNA fragments are:

[4 Marks]
  • (A) Positively charged
  • (B) Either positively or negatively charged depending on their size
  • (C) Neutral
  • (D) Negatively charged
Explanation:

DNA fragments are negatively charged because presence of phosphate group.

Question 144.

Which of the following RNAs should be most abundant

in animal cell?

[4 Marks]
  • (A) mi-RNA
  • (B) rRNA
  • (C) t-RAN
  • (D) m-RNA
Explanation:

Ribosomal RNA (rRNA) is most abundant in animal cell. It constitutes 80% of total RNA of the cell.

Question 145.

The association of histone H1 with a nucleosome indicates:

[4 Marks]
  • (A) DNA replication is occurring.
  • (B) The DNA is condensed into a Chromatin Fibre.
  • (C) The DNA double helix is exposed.
  • (D) Transcription is occurring.
Explanation:

The association of H1 protein indicates the complete formation of nucleosome which requires DNA condensa tion. The DNA is therefore in condensed form.

Question 146.

If there are 999 bases in an RNA that codes for a protein with 333 amino acids, and the base at position 901 is deleted such that the length of the RNA becomes 998 bases, how many codons will be altered?

[4 Marks]
  • (A) 11
  • (B) 33
  • (C) 1
  • (D) 333
Explanation:

If deletion happens at 901st position then the remaining 98 bases specifying for 33 codons of amino acids will be altered

Question 147.

During DNA replication, Okazaki fragments are used to

elongate:

[4 Marks]
  • (A) The leading strand towards replication fork.
  • (B) The lagging strand towards replication fork.
  • (C) The lagging strand away from the replication fork.
  • (D) The leading strand away from replication fork .
Explanation:

Two DNA polymerase molecules simultaneously work at the DNA fork, one on the leading strand and the other on the lagging strand. DNA polymerase synthesizes each Okazaki fragment a laggIing strand in 5'-3' direction. As the replication fork opens further, new Okazaki fragments appear. The first Okazaki fragment appears away from the replication fork and thus the direction of elongation would be away from replication fork.

Question 148.

Spliceosomes are not found in cells of;

[4 Marks]
  • (A) Bacteria
  • (B) Plants
  • (C) Animals
  • (D) Fungi
Explanation:

In eukaryotes, spliceosomes are used in removal of introns during post-transcriptional processing of hnRNA. they are absent in prokaryotes.

Question 149.

Which of the following represents order of Horse’?

[4 Marks]
  • (A) Perissodactyla
  • (B) Caballus
  • (C) Equidae
  • (D) Ferus
Explanation:

Horse belongs to

Orders - Perissodactyla

Family - Equidae

Genus - Equus

Species - ferus

‘Subspecies - caballus

Question 150.

Transplantation of tissues/organs fails often due to non-acceptance by the patient’s body. Which type of immune-response is responsible for such rejections

[4 Marks]
  • (A) Physiological immune response
  • (B) Hormonal immune response
  • (C) Autoimmune response
  • (D) Cell-mediated immune response
Explanation:

Cell mediated immune response causes non-acceptance o rejection of graft or transplanted tissues/organs.Transplant rejection is caused primarily by a cell-mediated jmmune response to HLA antigens expressed on donor . antigen-presenting cells (APCs) transferred along with the transplanted organ. Recognition of donor HLA antigens on the cells of the graft induces vigorous T cell proliferation

in the recipient.

Question 151.

MALT constitutes about ............. percent of the lymphoid tissue in human body.

[4 Marks]
  • (A) 50%
  • (B) 10%
  • (C) 70%
  • (D) 20%
Explanation:

MAL Mucosa Associated Lymphoid Tissue constitutes about 50 percent of the lymphoid tissue in human body. It is scattered along mucosal lining in the human body

Question 152.

Homozygous pure lines in cattle can be obtained by:

[4 Marks]
  • (A) mating of individuals of different species.
  • (B) mating of related individuals of same breed.
  • (C) mating of unrelated individuals of same breed.
  • (D) mating of individuals of different breed.
Explanation:

Inbreeding increases homozygosity. So, mating ofthe related indi viduals of same breed will give homozygous

purelines.

Question 153.

‘Which of the following in sewage treatment removes suspended solids?

[4 Marks]
  • (A) Sludge treatment
  • (B) Secondary treatment
  • (C) Primary treatment
  • (D) Tertiary treatment
Explanation:

Primary treatment is a physical process which involves two process, i.e. filtration and sedimentation of big solid waste.

Question 154.

‘Which of the following is correctly matched for the product produced by them ?

[4 Marks]
  • (A) Penicillium notatum : Acetic acid
  • (B) Methanobacterium : Lactic acid
  • (C) Sacchromyces cerevisiae : Ethanol
  • (D) Acetobacter aceti : Antibiotics
Explanation:

Saccharomyces cerevisiae commonly know as Brewer’s yeast, causes fermentation of carbohydrates and produces ethanol.

Question 155.

The DNA fragments separated on an agarose gel can be visualised after staining with:

[4 Marks]
  • (A) Acetocarmine
  • (B) Aniline blue
  • (C) Bromophenol blue
  • (D) Ethidium bromide
Explanation:

Ethidium bromide (EtBr) is used to stain the DNA fragments and will appear as orange coloured ‘bands when kept under UV light.

Question 156.

A gene whose expression helps to identify transformed cell is known as :

[4 Marks]
  • (A) Plasmid
  • (B) Vector
  • (C) Selectable marker
  • (D) Structural gene
Explanation:

Selectable markers in recombinant DNA technology,

helps in identification and elimination of ‘non-transformants

and selectively permits the growth of the transformants.

Question 157.

‘What is the criterion for DNA fragments movement on agarose gel during gel electrophoresis?

[4 Marks]
  • (A) Negatively charged fragments do not move
  • (B) Positively charged fragments move to farther end
  • (C) The larger the fragment size, the farther it moves
  • (D) The smaller the fragment size, the farther it moves
Explanation:

DNA fragments during gel electrophoresis, separate

(resolve) according to their size due to sieving effect provided by agarose gel.

Question 158.

The process of separation and purification of expressed protein before marketing is called:

[4 Marks]
  • (A) Downstream processing
  • (B) Postproduction processing
  • (C) Bioprocessing
  • (D) Upstream processing
Explanation:

The various stages of processing that occur after the completion of fermentation or biosynthetic stage which include separation and purification of product called downstream processing.

Question 159.

Presence of plants arranged into well defined vertical layers depending on their height can be seen best in:

[4 Marks]
  • (A) Tropical Rain Forest
  • (B) Grassland
  • (C) Tropical Savannah
  • (D) Temperate Forest
Explanation:

The tropical rain forest have five vertical strata on the basis of plants height i.e., ground vegetation, shrubs, short canopy trees, tall canopy trees and tall emergent trees.

Question 160.

Asymptote in a logistic growth curve is obtained when :

[4 Marks]
  • (A) K>N
  • (B) K=N
  • (C) The value of ‘r’ approaches zero
  • (D) K
Explanation:

In logistic growth curve, the curve has an upper asymptote known as carrying capacity (K) is obtained when the maximum population size is at dN/dt = 0. A population growing in a habitat with limited resources shows logistic growth curve.
For logistic growth,
dN/dt = rN[(K − N)/K]
If K = N then
(K − N)/K = 0

∴ dN/dt =0.

The population reaches asymptote.

Question 161.

Mycorrhizae are the example of :

[4 Marks]
  • (A) Amensalism
  • (B) Antibiosis
  • (C) Mutualism
  • (D) Fungistasis
Explanation:

Mycorrhizaeis a symbiotic association between fungi and roots of higher plants.

Question 162.

Which ecosystem has the maximum biomass?

[4 Marks]
  • (A) Forest ecosystem
  • (B) Pond ecosystem
  • (C) Lake ecosystem
  • (D) Grassland ecosystem
Explanation:

Forest ecosystem has the maximum biomass.

Some very high productive ecosystem are

— Tropical rain forest

— Coral reef

— Estuaries

— Sugarcane fields

Question 163.

Alexander Von Humboldt described for the first time:

[4 Marks]
  • (A) Species-Area relationships
  • (B) Population Growth equation
  • (C) Laws of limiting factor
  • (D) Ecological Biodiversity
Explanation:

Alexander Von Humboldt noticed that within a region species richness increases with the increase in area.

Question 164.

‘Which one of the following statements is not valid for aerosols?

[4 Marks]
  • (A) They are harmful to human health
  • (B) They have negative impact on agricultural land
  • (C) They cause increased agricultural productivity
  • (D) They alter rainfall and monsoon patterns
Explanation:

Aerosols through its direct or indirect effects on plants can cause various problems in agriculture. However, continuous increase in air pollution may represent a threat to agriculture in the future that is persistent and largely irreversible.

Question 165.

Artificial selection to obtain cows yielding higher milk

output represents :

[4 Marks]
  • (A) Directional as it pushes the mean of the character in one direction
  • (B) Disruptive as it splits the population into two, one yielding higher output and the other lower output
  • (C) Stabilizing followed by disruptive as it stabilizes the population to produce higher yielding cows
  • (D) Stabilizing selection as it stabilizes this character in the population
Explanation:

Artificial selection to obtain cow yielding higher milk output will shift the peak to one direction, so this represent an example of Directional selection. In stabilizing selection, the organisms with the mean value of the trait are selected. In disruptive selection, both extremes get selected.

Question 166.

Select the mismatch :

[4 Marks]
  • (A) Rhodospirillum - Mycorrhiza
  • (B) Rhizobium - Alfalfa
  • (C) Frankia - Alnus
  • (D) Anabaena - Nitrogen fixer
Explanation:

Rhodospirillum is facultative anaerobe and free living nitrogen fixer. Mycorrhiza show symbiotic relationship between fungi and roots of higher plants.

Question 167.

Which one of the following is related to Ex-situ conservation of threatened animals and plants ?

[4 Marks]
  • (A) Wildlife safari parks
  • (B) Amazon rainforest
  • (C) Himalayan region
  • (D) Biodiversity hotspots
Explanation:

Ex-situ conservation is offsite strategy for conservation of biological diversity in zoological park and botanical gardens respectively.

Question 168.

A temporary endocrine gland in the human body is:

[4 Marks]
  • (A) Pineal gland
  • (B) Corpus allatum
  • (C) Corpus cardiacum
  • (D) Corpus luteum
Explanation:

Corpus luteum is the temporary endocrine gland formed in the ovary after ovulation. It release hormones like progesterone, oestrogen etc.

Question 169.

Match the following sexually transmitted diseases (Column-I) with their causative agent (Column-II) and select

the correct option :

[4 Marks] Diagram 45 – NEET-UG 2017 Question Paper Solutions
  • (A) A-iii B-iv C-i D-ii
  • (B) A-iv B-ii C-iii D-i
  • (C) A-ii B-iii C-iv D-i
  • (D) A-iv B-iii C-ii D-i
Explanation:

Gonorrhoea – Neisseria (Bacteria)
Syphilis – Treponema (Bacteria)
Genital Warts – Human papilloma virus
AIDS – HIV (Virus)

Question 170.

‘Which of the following in sewage treatment removes suspended solids

[4 Marks]
  • (A) Secondary treatment
  • (B) Sludge treatment
  • (C) Primary treatment
  • (D) Tertiary treatmen
Explanation:

Primary treatment is a physical process which involves two process, i.e. filtration and sedimentation of big solid waste.

Question 171.

Select the correct route for the passage of sperms in male frogs:

[4 Marks]
  • (A) Testes → Vasa efferentia → Bidder’s canal → Ureter → Cloaca
  • (B) Testes → Vasa efferentia → Kidney → Bidder’s canal → Urinogenital duct → Cloaca
  • (C) Testes —> Vasa efferentia —> Kidney —> Seminal Vesicle—> Urinogenital duct—> Cloaca
  • (D) Testes → Bidder’s canal → Kidney → Vasa efferentia → Urinogenital duct → Cloaca
Explanation:

In male frog the sperms passage is:
Testes → Vasa efferentia → Kidney → Bidder's canal → Urinogenital duct → Cloaca.

Question 172.

GnRH, a hypothalamic hormone, needed in reproduction, acts on:

[4 Marks]
  • (A) anterior pituitary gland and stimulates secretion of LH and FSH.
  • (B) posterior pituitary gland and stimulates secretion of LH and relaxin.
  • (C) anterior pituitary gland and stimulates secretion of LH and oxytocin.
  • (D) posterior pituitary gland and stimulates secretion of oxytocin and FSH.
Explanation:

GnRH is secreted by hypothalamus which stimulates anterior pituitary gland for the secretion of gonadotropins (FSH and LH).

Question 173.

Identify the wrong statement in context of heartwood:

[4 Marks]
  • (A) Organic compounds are deposited in it
  • (B) It comprises dead elements with highly lignified walls
  • (C) It conducts water and minerals efficiently
  • (D) It is highly durable
Explanation:

Heartwood is inactive physiologically due to deposition of organic compounds and formation of tyloses so it will not conduct water and minerals.

Question 174.

Consider a drop of rain water having mass 1 g falling from a height of 1 km. It hits the ground with a speed of 50 m/s. Take 'g' constant with a value 10 m/s². The work done by the(i) gravitational force and

(ii) resistive force of air is

[4 Marks]
  • (A) (i) 1.25 J (ii) −8.25 J
  • (B) (i) 10 J (ii) −8.75 J
  • (C) (i) −10 J (ii) −8.25 J
  • (D) (i) 100 J (ii) 8.75 J
Explanation:

From work-energy theorem,

W_g + W_a = ΔK.E.

or, mgh + W_a = 1/2 mv² − 0

10⁻³ × 10 × 10³ + W_a = 1/2 × 10⁻³ × (50)²

⇒ W_a = −8.75 J

which is the work done due to air resistance

Work done due to gravity = mgh
= 10⁻³ × 10 × 10³ = 10 J

Question 175.

Which of the following statements are correct?

(A) Centre of mass of a body always coincides with the centre of gravity of the body.
(B) Centre of mass of a body is the point at which the total gravitational torque on the body is zero.
(C) A couple on a body produce both translational and rotation motion in a body.
(D) Mechanical advantage greater than one means that small effort can be used to lift a large load.

[4 Marks]
  • (A) (B) and (D)
  • (B) (C) and (D)
  • (C) (B) and (C)
  • (D) (A) and (B)
Explanation:

Mechanical advantage, M.A = Load/Effort

If M.A. > 1 ⇒ Load > Effort

Question 176.

Predict the correct intermediate and product in the following reaction

[4 Marks] Diagram 46 – NEET-UG 2017 Question Paper Solutions
  • (A) Diagram 47 – NEET-UG 2017 Question Paper Solutions
  • (B) Diagram 48 – NEET-UG 2017 Question Paper Solutions
  • (C) Diagram 49 – NEET-UG 2017 Question Paper Solutions
  • (D) Diagram 50 – NEET-UG 2017 Question Paper Solutions
Explanation:

Hydration of alkynes give ketones.

Diagram 51 – NEET-UG 2017 Question Paper Solutions
Question 177.

Match the interhalogen compounds of column-I with the geometry in column Il and assign the correct code.

[4 Marks] Diagram 52 – NEET-UG 2017 Question Paper Solutions
  • (A) 1-iii 2-iv 3-i 4-ii
  • (B) 1-iv 2-iii 3-ii 4-i
  • (C) 1-v 2-iv 3-iii 4-ii
  • (D) 1-iii 2-i 3-iv 4-ii
Explanation:

XX' → Linear (e.g. ClF, BrF)

XX₃' → T-Shape (e.g. ClF₃, BrF₃)

XX₅' → Square pyramidal (e.g. BrF₅, IF₅)

XX₇' → Pentagonal bipyramidal (e.g. IF₇)

Question 178.

Which one is the most acidic compound ?

[4 Marks]
  • (A) Diagram 53 – NEET-UG 2017 Question Paper Solutions
  • (B) Diagram 54 – NEET-UG 2017 Question Paper Solutions
  • (C) Diagram 55 – NEET-UG 2017 Question Paper Solutions
  • (D) Diagram 56 – NEET-UG 2017 Question Paper Solutions
Explanation:

Electron withdrawing—NO₂, group has very strong -I

and —R effects so, compound 3 will be most acidic.

Question 179.

Identify A and predict the type of reaction

[4 Marks] Diagram 57 – NEET-UG 2017 Question Paper Solutions
  • (A) Diagram 58 – NEET-UG 2017 Question Paper Solutions
  • (B) Diagram 59 – NEET-UG 2017 Question Paper Solutions
  • (C) Diagram 60 – NEET-UG 2017 Question Paper Solutions
  • (D) Diagram 61 – NEET-UG 2017 Question Paper Solutions
Explanation:

More stable as —ve charge is close to electron withdrawing group.

Also, incoming nucleophile gets attached on same 'C'on

which 'Br' (Leaving group) was present.

. nota cine substitution reaction.

Diagram 62 – NEET-UG 2017 Question Paper Solutions
Question 180.

out of the following, which is the product formed when cyclohexanone undergoes aldol condensation followed by heating ?

[4 Marks]
  • (A) Diagram 63 – NEET-UG 2017 Question Paper Solutions
  • (B) Diagram 64 – NEET-UG 2017 Question Paper Solutions
  • (C) Diagram 65 – NEET-UG 2017 Question Paper Solutions
  • (D) Diagram 66 – NEET-UG 2017 Question Paper Solutions
Explanation:

More stable as —ve charge is close to electron withdrawing group.

Also, incoming nucleophile gets attached on same 'C'on

which 'Br' (Leaving group) was present.

. nota cine substitution reaction.

Diagram 67 – NEET-UG 2017 Question Paper Solutions