CBSE EXAMINATION PAPER-2011
NEET-ZOOLOGY
(Solved)
General Instructions :
Read the following instructions carefully and follow them :
- This question paper contains 200 questions. All questions are compulsory.
- This question paper is divided into 1 sections.
- Section A – questions number 1 to 200 are multiple choice questions
- There is no overall choice given in the question paper. However, an internal choice has been provided in few questions.
- Use of calculator is NOT allowed.
Section A
A body is moving with velocity 30 m/s towards east. After 10 seconds its velocity becomes 40 m/s towards north. The average acceleration of the body is
Average acceleration
<a>= Change in velocity / Total Time.
<a>= |40ĵ - 30î| / 10
<a>= √(4² + (-3)²)
<a>= 5 m/s².
A boy standing at the top of a tower of 20m height drops a stone. Assuming g=10 ms⁻², the velocity with which it hits the ground is
Here, u = 0. We have, v² = u² + 2gh ⇒ v = √(2gh) = √(2 × 10 × 20) = 20 m/s.
A missile is fired for maximum range with an initial velocity of 20 m/s. If g=10 m/s² the range of the missile is
For maximum range, the angle of projection, θ = 45°.
∴ R = u²sin(2θ)/g
= (20)²sin(2×45°)/10 = 400×1/10
= 40 m.
A particle moves in a circle of radius 5 cm with constant speed and time period 0.2π s. The acceleration of the particle is
Centripetal acceleration a_c = ω²r = (2π/T)²r = (2π/0.2π)² × 5 × 10⁻² = 5 m/s².
A body of mass M hits normally a rigid wall with velocity V and bounces back with the same velocity. The impulse experienced by the body is
Impulse experienced by the body = change in momentum
= MV - (-MV)
= 2MV.
A person of mass 60 kg is inside a lift of mass 940 kg and presses the button on control panel. The lift starts moving upwards with an acceleration 1.0 m/s². If g=10 ms⁻² the tension in the supporting cable is
Total mass = (60 + 940) kg = 1000 kg.
Let T be the tension in the supporting cable, then T - 1000g = 1000 × 1
⇒ T = 11000N.
The potential energy of a system increases if work is done
When work is done by the system against a conservative force, its potential energy increases
A body projected vertically from the earth reaches a height equal to earth's radius before returning to the earth. The power exerted by the gravitational force is greatest
Power exerted by a force is given by P = F.v. When the body is just above the earth's surface, its velocity is greatest. At this instant, gravitational force is also maximum. Hence, the power exerted by the gravitational force is greatest at the instant just before the body hits the earth.
The instantaneous angular position of a point on a rotating wheel is given by the equation θ(t) = 2t³ - 6t². The torque on the wheel becomes zero at
θ(t) = 2t³ - 6t²
⇒ dθ/dt = 6t² - 12t ⇒ α = d²θ/dt²
= 12t - 12 = 0
∴ t = 1 s
The moment of inertia of a thin uniform rod of mass M and length L about an axis passing through its midpoint and perpendicular to its length is I₀. Its moment of inertia about an axis passing through one of its ends and perpendicular to its length is
By theorem of parallel axes,
I = I_cm + Md²
I = I₀ + M(L/2)² = I₀ + ML²/4.
A planet moving along an elliptical orbit is closest to the sun at a distance r₁ and farthest away at a distance of r₂. If v₁ and v₂ are the linear velocities at these points respectively, then the ratio v₁/v₂ is
Angular momentum is conserved. ∴ L₁ = L₂
⇒ mr₁v₁ = mr₂v₂
⇒r₁v₁ = r₂v₂
⇒ v₁/v₂ = r₂/r₁.
During an isothermal expansion, a confined ideal gas does -150 J of work against its surroundings. This implies that
According to question work done by gas is given -150J so that according to it answer will be 150 J of heat has been added to the gas
When 1 kg of ice at 0°C melts to water at 0°C, the resulting change in its entropy, taking latent heat of ice to be 80 cal /°C , is
Change in entropy is given by
ΔS = dQ/T or ΔS = ΔQ/T= mL_f / 273
ΔS= (1000 × 80) / 273 = 293 cal/K.
A particle of mass m is released from rest and follows a parabolic path as shown. Assuming that the displacement of the mass from the origin is small, which graph correctly depicts the position of the particle as a function of time
The given velocity-position graph depicts that the motion of the particle is SHM.
In SHM, at t=0, v=0 and x = x_max.
Out of the following functions, representing motion of a particle, which represents SHM?
(A) y = sin(ωt) - cos(ωt)
(B) y = sin³(ωt)
(C) y = 5 cos(3π/4 - 3ωt)
(D) y = 1 + ωt + ω²t²
Only functions given in (A) & (C) represent SHM.
Two waves are represented by the equations y₁ = a sin(ωt + kx + 0.57) m and y₂ = a cos(ωt + kx) m, where x is in meter and t in sec. The phase difference between them is
Here, y₁ = a sin(ωt + kx + 0.57)
so, ϕ₁ = 0.57
and y₂ = a cos(ωt + kx)
= a sin[π/2 + (ωt + kx)]
So, ϕ₂ = π/2
Phase difference, Δϕ = ϕ₂ - ϕ₁
= π/2 - 0.57 = 3.14/2 - 0.57
= 1.57 - 0.57 = 1 radian.
Sound waves travel at 350 m/s through a warm air and at 3500 m/s through brass. The wavelength of a 700 Hz acoustic wave as it enters brass from warm air
We have, v = nλ.
⇒ v ∝ λ (as n remains constant). Thus, as v increases 10 times , λ also increases 10 times.
A charge Q is enclosed by a Gaussian spherical surface of radius R. If the radius is doubled, then the outward electric flux will
By Gauss's theorem,
ϕ = Q_in / ε₀.
Thus, the net flux depends only on the charge enclosed by the surface. Hence, there will be no effect on the net flux if the radius of the surface is doubled
Four electric charges +q, +q, -q and -q are placed at the corners of a square of side 2L. The electric potential at point A, midway between the two charges +q and +q, is
Distance of point A from the two +q charges = L.
Distance of point A from the two -q charges = √(L² + (2L)²) = √5 L.
∴ V_A = (Kq/L × 2) - (Kq/√5L × 2)
= (2Kq/L)[1 - 1/√5]
= (1/4πε₀) (2q/L) (1 - 1/√5).
A current of 2A flows through a 2Ω resistor when connected across a battery. The same battery supplies a current of 0.5 A when connected across a 9Ω resistor. The internal resistance of the battery is
Let the internal resistance of the battery be r. Then the current flowing through the circuit is given by
i = E / (R + r).
In first case,
2 = E / (2 + r). .......(i)
In second case,
0.5 = E / (9 + r). ......(ii)
From (i) & (ii),
4 + 2r = 4.5 + 0.5r
⇒ 1.5r = 0.5 ⇒ r = 1/3 Ω.
The rate of increase of thermo-e.m.f. with temperature at the neutral temperature of a thermocouple
We have, e = at + bt².
⇒ de/dt = a + 2bt.
At neutral temperature,
t = -a/2b
∴ de/dt = 0.
A uniform electric field and uniform magnetic field are acting along the same direction in a certain region. If an electron is projected in the region such that its velocity is pointed along the direction of fields, then the electron
𝐯⃗ and 𝐁⃗ are in the same direction, so the magnetic force on the electron becomes zero. But force on the electron due to the electric field is opposite to the direction of velocity
If power dissipated in the 9-Ω resistor in the circuit shown is 36 watt, the potential difference across the 2-Ω resistor is
We have, P = V²/R ⇒ 36 = V²/9
⇒ V = 18V.
Current passing through the 9Ω resistor is
i₁ = V/R = 18/9 = 2A.
The 9Ω and 6Ω resistors are in parallel, therefore
i₁ = 6/9+6 × i
where i is the current delivered by the battery.
∴ i = 2×15/6 = 5A
Thus, Potential difference across 2Ω resistor is V = iR = 5 × 2 = 10V.
A current carrying loop in the form of a right angle isosceles triangle ABC is placed in a uniform magnetic field acting along AB. If the magnetic force on the arm BC is F, what is the force on the arm AC?
Leta current i be flowing in the loop ABC in the direction shown in the figure. If the length of each of the
sides AB and BC be x then
|𝐅⃗| =i x B
where B is the magnitude of the magnetic force.
The direction of 𝐅⃗ will be n the direction perpendicular to the plane of the paper and going into it.
By Pythagorus theorem,
AC = √ x² + x² = √2x
∴ Magnitude of force on AC
= i√2× B sin 45°
= i√2xB × 1/√2
= ixB = |𝐅⃗|
The direction of the force on AC is perpendicular to the plane of the paper and going out of it. Hence, force on AC = -𝐅⃗
There are four light-weight-rod samples A, B, C, D separately suspended by threads. A bar magnet is slowly brought near each sample and the following observations are noted:
(i) A is feebly repelled
(ii) B is feebly attracted
(iii) C is strongly attracted
(iv) D remains unaffected.
Which one of the following is true?
A → diamagnetic,
B → paramagnetic,
C → ferromagnetic,
D → non-magnetic.
The current i in a coil varies with time as shown in the figure. The variation of induced emf with time would be
e = -L(di/dt).
During 0 to T/4, di/dt = const.
∴ e = -ve
During T/4 to T/2, di/dt = 0,
∴ e = 0
During T/2 to 3T/4, di/dt = const.
∴ e = +ve
Thus graph given in option (a) represents the variation of induced emf with time.
In an ac circuit an alternating voltage e = 200√2 sin 100t volts is connected to a capacitor of capacity 1 µF. The r.m.s. value of the current in the circuit is
V_rms = 200√2 / √2 = 200V.
I_rms = V_rms / X_C = (200 / 1) / (100 × 10⁻⁶)
= 2 × 10⁻² = 20mA.
An ac voltage is applied to a resistance R and an inductor L in series. If R and the inductive reactance are both equal to 3Ω, the phase difference between the applied voltage and the current in the circuit is
The phase difference φ is given by tan ϕ = X_L / R = 3 / 3 = 1.
→ ϕ = π/4
The electric and the magnetic field associated with an E.M. wave, propagating along the +z-axis, can be represented by
E.M. wave always propagates in a direction perpendicular to both electric and magnetic fields. So, electric and magnetic fields should be along + X and + Y—
directions respectively.
The decreasing order of wavelength of infrared, microwave, ultraviolet and gamma rays is
The decreasing order of the wavelengths is as given below: microwave, infrared, ultraviolet, gamma rays.
Which of the following is not due to total internal reflection?
Difference between apparent and real depth of a pond is due to the refraction of light, not due to the total internal reflection. Other three phenomena are due to the total internal reflection.
A biconvex lens has a radius of curvature of magnitude 20 cm. Which one of the following options best describe the image formed of an object of height 2 cm placed 30 cm from the lens?
R = 20 cm
h₀ = 2
u = - 30 cm
We have, 1/f = (μ-1)(1/R₁ - 1/R₂)
= (3/2-1)(1/20 - (-1/20))
⇒ 1/f = (3/2-1) × 2/20
∴ f = 20 cm
1/f = 1/v - 1/u ⇒1/20 = 1/v + 1/ 30
1/v = 1/20 - 1/30 = 10/600
v = 60 cm
m = hᵢ / h₀ = v/u
⇒ hᵢ = v/u× h₀ = 60 / 30 × 2
= -4 cm.
So, image is inverted
Electrons used in an electron microscope are accelerated by a voltage of 25 kV. If the voltage is increased to 100kV then the de-Broglie wavelength associated with the electrons would
λ ∝ 1/√V
⇒ λ₁/λ₂ = √(V₂/V₁) = √(100keV/25keV) = 2
⇒ λ₂ = λ₁/2
In the Davisson and Germer experiment, the velocity of electrons emitted from the electron gun can be increased by
In the Davisson and Germer experiment, the velocity of electrons emitted from the electron gun can be increased by increasing the potential difference between the anode and filament.
Photoelectric emmision occurs only when the incident light has more than a certain minimum
For occurrence of photoelectric effect, the incident light should have frequency more than a certain minimum which is called the threshold frequency (ν₀).
Light of two different frequencies whose photons have energies 1 eV and 2.5 eV respectively illuminate a metallic surface whose work function is 0.5 eV successively. Ratio of maximum speeds of emitted electrons will be
The maximum kinetic energy of emitted electrons is given by
K.E. = ϕ - ϕ₀
K.E₁ = 1 eV - 0.5 eV = 0.5 eV.
K.E₂ = 2.5 eV - 0.5 eV = 2 eV
∴ K.E₁/K.E₂ = 0.5eV/ 2eV =1/4
⇒ v₁/v₂ = √(1/4) = 1/2
In photoelectric emission process from a metal of work function 1.8 eV, the kinetic energy of most energetic electrons is 0.5 eV. The corresponding stopping potential is
The stopping potential is numerically equal to the maximum kinetic energy.
The wavelength of the first line of Lyman series for hydrogen atom is equal to that of the second line of Balmer series for a hydrogen like ion. The atomic number Z of hydrogen like ion is
For first line of Lyman series of hydrogen,
hc/λ₁ = Rhc(1/1² - 1/2²).
For second line of Balmer series of hydrogen like ion,
hc/λ₂ = Z²Rhc(1/2² - 1/4²)
By question, λ₁ = λ₂,
⇒ (1/1 - 1/2) = Z²(1/4 - 1/16)
or Z = 2
The power obtained in a reactor using U²³⁵ disintegration is 1000 kW. The mass decay of U²³⁵ per hour is
E = mc²
m = E/c²
So, Mass decay per second
dm/dt = 1/c² dE/dt = 1 / c²(Power in watt)
= 1/(3×10⁸)² × 1000 × 10³
and mass decay per hour = dm/dt ×60 × 60
= 1/(3×10⁸)² × 10⁶ × 3600
= 4 × 10⁻⁸ kg
= 40 microgram.
A nucleus of mass M emits a photon of frequency v and the nucleus recoils. The recoil energy will be
Momentum Mu = E/c = hv/c. Recoil energy = 1/2 Mu²
= 1/2 M²u²/M = 1 / 2M (hv/c)²
= h²v² / 2Mc².
Fusion reaction takes place at high temperature because
When the coulomb repulsion between the nuclei is overcome then nuclear fusion reaction takes place. This is possible when the temperature is too high.
The half life of a radioactive isotope 'X' is 50 years. It decays to another element 'Y' which is stable. The two elements 'X' and 'Y' were found to be in the ratio of 1: 15 in a sample of a given rock. The age of the rock was estimated to be
Let number of atoms in X = Nₓ
Number of atoms in Y = N_y
By question
Nₓ / N_y = 1 / 15
∴ Part of Nₓ = 1/16 (Nₓ + N_y)
=1/2⁴(Nₓ + N_y)
So, total 4 half-lives are passed, so age of rock is 4 × 50 = 200 years.
A nucleus ᵐₙX emits one α-particle and two β-particles. The resulting nucleus is
When ᵐₙX emits one α-particle, its atomic mass decreases by 4 units and atomic number by 2. Therefore, the new nucleus becomes ᵐ⁻⁴ₙ₋₂Y. But as it emits two β particles, its atomic number increases by 2. Thus the resulting nucleus is ᵐ⁻⁴ₙX.
In forward biasing of the p-n junction
In forward biasing of the p-n junction, the positive terminal of the battery is connected to p-side and the negative terminal of the battery is connected to n-side. The depletion region becomes thin.
An ideal junction diode when forward biased offers zero resistance. Voltage drop across such a junction diode is zero. In reverse bias diode offers infinite resistance and voltage drop across it is equal to voltage applied.
If a small amount of antimony is added to germanium crysts
When small amount of antimony (pentavalent) is added to germanium crystal then crystal becomes n-type semi conductor. Therefore, there will be more free electrons than holes in the semiconductor.
A transistor is operated in common emitter configuration at V_c = 2V such that a change in the base current from 100 µA to 300 µA produces a change in the collector current from 10 mA to 20 mA. The current gain is
The current gain
β = ΔI_C / ΔI_B = 10mA / 200µA
= (10 × 10³) / 200 = 50.
A parallel plate capacitor has a uniform electric field E in the space between the plates. If the distance between the plates is d and area of each plate is A, the energy stored in the capacitor is:
The energy stored by a capacitor U = 1/2 C V² .....(i)
V is the p.d. between two plates of the capacitor potential difference
V = E.d
The capacitance of the parallel plate capacitor
C = Aε₀/d
substituting the value of C in equation (i)
U = 1/2 (Aε₀/d)(Ed)² = 1/2 ε₀ E² A d
The energies E₁ and E₂ of two radiations are 25 eV and 50 eV, respectively. The relation between their wavelengths i.e., λ₁ and λ₂ will be:
Given E₁ = 25 eV E₂ = 50 eV
E₁ = hc/λ₁ and E₂ = hc/λ₂.
∴ E₁/E₂ = λ₂/λ₁
∴ λ₂/λ₁ = 25/50 = 1/2
∴ λ₁ = 2λ₂.
If n = 6, the correct sequence for filling of electrons will be:
When n = 6, the sequence of filling of electrons: 6s → 4f → 5d → 6p or ns → (n-2)f → (n-1)d → np
The total number of atomic orbitals in fourth energy level of an atom is:
Total no. of atomic orbitals in a shell = n². Given n = 4, hence number of atomic orbitals in 4th shell will be 16.
Which of the two ions from the list given below that have the geometry that is explained by the same hybridization of orbitals, NO₂⁻, NO₃⁻, NH₂⁻, NH₄⁺, SCN⁻?
NO₂⁻, H = 1/2[5+0+1-0] = 3= (sp²)
NO₃⁻, H = 1/2[5+0+1-0] = 3 =(sp²)
NH₂⁻, H = 1/2[5+2+1-0] = 4 =(sp³)
NH₄⁺, H = 1/2[5+4+0-1] = 4 (sp³)
SCN⁻, H =1/2[4+0+0+0] = 2 = (sp)
∴ NO₂⁻ and NO₃⁻ have the same hybridization.
Considering the state of hybridization of carbon atoms, find out the molecule among the following which is linear?
.
Which of the following has the minimum bond length?
O₂ (16) : KK (σ 2s)² (σ* 2s)² (σ 2p_z)² (π 2p_x)² (π 2p_y)², (π*₂ p_y)¹ = (π*₂p_x)¹, B.O. : 2
O₂⁺ (15) : Remove one electron from π*2p_y from O₂, B.O. : 2.5
O₂⁻ (17) : KK (σ 2s)² (σ* 2s)² (σ 2p_z)² (π 2p_x)² (π 2p_y)², (π* 2p_x)² (π* 2p_y)¹, B.O. : 1.5
O₂²⁻ (18) : KK (σ 2s)² (σ* 2s)² (σ 2p_z)² (π 2p_x)² (π 2p_y)², (π* 2p_x)² (π* 2p_y)²
Since, the bond length decreases as the bond order increases, hence, O₂⁺ have least bond length.
Two gases A and B having the same volume diffuse through a porous partition in 20 and 10 seconds respectively. The molecular mass of A is 49 u. Molecular mass of B will be:
r_A / r_B = √(M_B / M_A)
(V / 20) / (V / 10) = √(M_B / 49)
⇒ 1/2 = √(M_B / 49)
M_B = 1/4 × 49 = 12.25u
By what factor does the average velocity of a gaseous molecule increase when the temperature (in Kelvin) is doubled?
Average velocity v = √(8RT/πM)
i.e., v ∝ √T
∴ V₂/V₁ = √(2T/T) = 1.41
A gaseous mixture was prepared by taking equal mole of CO and N₂. If the total pressure of the mixture was found 1 atmosphere, the partial pressure of the nitrogen (N₂) in the mixture is:
Given n_CO = ⁿN₂
P_CO + P_N₂ = 1 atm
Partial pressure of a gas
= mole fraction of gas × total pressure
∴ P_N₂ = (ⁿN₂ / (ⁿCO + ⁿN₂)) × 1 = (ⁿN₂ / ²ⁿN₂) × 1 = 1/2 = 0.5 atm.
Which of the following is correct option for free expansion of an ideal gas under adiabatic condition?
For adiabatic process ΔQ = 0.
In free expansion, external pressure is zero. Thus, work done w = 0 and ΔE = w = 0. If ΔE = 0, then ΔT = 0.
Enthalpy change for the reaction, 4H(g) → 2H₂(g) is -869.6 kJ. The dissociation energy of H-H bond is:
Given
4H(g) → 2H₂(g); ΔH = -869.6 kJ.
or 2H₂(g) → 4H(g); ΔH = 869.6 kJ. H₂(g) → 2H(g); ΔH = 869.6 / 2
= 434.8 kJ.
If the enthalpy change for the transition of liquid water to steam is 30 kJ mol⁻¹ at 27°C, the entropy change for the process would be:
Given ΔH = 30 kJ mol⁻¹ T = 273 + 27 = 300 K
ΔS_T = ΔH_T / T
= (3 × 10⁴) / 300 J mol⁻¹
= 100 J mol⁻¹ K⁻¹
For the reaction N₂(g) + O₂(g) ⇌ 2NO(g), the equilibrium constant is K₁. The equilibrium constant is K₂ for the reaction 2NO(g) + O₂(g) ⇌ 2NO₂(g). What is K for the reaction NO₂(g) ⇌ 1/2 N₂(g) + O₂(g)?
For the reaction N₂(g) + O₂(g) ⇌ 2NO(g)
K₁ = [NO]² / ([N₂][O₂])
For the reaction 2NO(g) + O₂(g) ⇌ 2NO₂(g)
K₂ = [NO₂]² / ([NO]²[O₂])
For the reaction NO₂(g) ⇌ 1/2 N₂(g) + O₂(g)
K = [N₂]¹ᐟ²[O₂] / [NO₂]
Hence, K = √(1 / (K₁ × K₂))
K = ([N₂]¹ᐟ²[O₂]¹ᐟ² / [NO]) × ([NO][O₂]¹ᐟ² / [NO₂]) = [N₂]¹ᐟ²[O₂] / [NO₂]
Which of the following is least likely to behave as Lewis base?
BF₃ behaves as a Lewis acid because it is an electron-deficient species
A buffer solution is prepared in which the concentration of NH₃ is 0.30 M and the concentration of NH₄⁺ is 0.20 M. If the equilibrium constant, K_b for NH₃ equals 1.8 × 10⁻⁵, what is the pH of this solution? (log 2.7 = 0.433).
Given : [NH₃] = 0.3 M, [NH₄⁺] = 0.2 M,
K_b = 1.8 × 10⁻⁵
pOH = pK_b + log ([salt] / [base]) [pK_b = -log K_b; pK_b = -log 1.8 × 10⁻⁵]
∴ pK_b = 4.74
pOH = 4.74 + log(0.2 / 0.3) = 4.74 + 0.3010 - 0.4771 = 4.56
pH = 14 - 4.56 = 9.436
Which one of the following is present as an active ingredient in bleaching powder for bleaching action?
The active ingredient in bleaching powder for bleaching action is Ca(OCl)₂.
Name the type of the structure of silicate in which one oxygen atom of [SiO₄]⁴⁻ is shared?
.
In Duma's method of estimation of nitrogen 0.35 g of an organic compound gave 55 mL of nitrogen collected at 300 K temperature and 715 mm pressure. The percentage composition of nitrogen in the compound would be: (Aqueous tension at 300 K = 15 mm)
Given wt of compound taken (w)=0.35g
Volume of nitrogen collected (V)= 55 mL.
Room temperature (tK)=300K
Atmospheric pressure (P) =715 mm
Aq. tension (p) = 15mm
Calculation -
Volume of N₂ at NTP= ((P - p) × V/ t) × 273 / 760mL
=(( 715 - 15) × 55 / 300) ×273 / 760
=46.098 mL
% of nitrogen
=28 x voL.of N₂ at NTP ×100 /
22400 × wt of organic compound
= 28 × 46.098 × 100 / 22400 × 0.35 =16.46%
The Lassaigne's extract is boiled with conc. HNO₃ while testing for halogens. By doing so it:
Conc. HNO₃ decomposes NaCN and Na₂S to avoid their interference.
NaCN + HNO₃ → NaNO₃ + HCN↑
Na₂S + 2HNO₃ → 2NaNO₃ + H₂S↑
Which one of the following is most reactive towards electrophilic reagent?
Due to +M effect of — OH group and hyperconjugation of —CH, group.
Which one of the following statement is not true?
The growth of fishes gets hindered if the concentration of (D.O.) is below 6 ppm.
The freezing point depression constant for water is -1.86 °C m⁻¹. If 5.00 g Na₂SO₄ is dissolved in 45.0 g H₂O, the freezing point is changed by -3.82 °C. Calculate the van't Hoff factor for Na₂SO₄.
Given K_f = - 1.86° cm⁻¹, mass of solute = 5.00 g, mass of solvent = 45.0 g
ΔT_f = i × K_f . m
3.82 = i × 1.86 × (5 × 1000) / (142 × 45) (Molecular mass of Na₂SO₄ = 142)
∴ i = 2.63
The van't Hoff factor i for a compound which undergoes dissociation in one solvent and association in other solvent is respectively:
If a compound dissociates in solvent i > 1 and on association i < 1.
Standard electrode potential of three metals X, Y and Z are -1.2 V, +0.5 V and -3.0 V, respectively. The reducing power of these metals will be:
As the value of standard reduction potential decreases, the reducing power increases i.e.,
Z (-3.0) > X (-1.2) > Y (+0.5).
The electrode potentials for
Cu²⁺(aq) + e⁻ → Cu⁺(aq)
and Cu⁺(aq) + e⁻ → Cu(s)
are +0.15 V and +0.50 V, respectively. The value of E° _Cu²⁺/Cu will be:
.
Standard electrode potential for Sn⁴⁺/Sn²⁺ couple is +0.15 V and that for the Cr³⁺/Cr couple is -0.74 V. These two couples in their standard state are connected to make a cell. The cell potential will be:
The couple for which SRP value is high, will act as cathode and the other couple will act as an anode.
E°_cell = E°_cathode - E°_anode = 0.15 V - (-0.74 V) = +0.89 V
If the E°_cell for a given reaction has a negative value, then which of the following gives the correct relationships for the values of ΔG° and K_eq?
Standard Gibbs free energy is given as
ΔG° = -nE°F
If E°_cell < 0 i.e. -ve
ΔG° > 0
Further ΔG° = -RT ln K_eq
∴ ΔG° > 0 when K_eq < 1
Which one of the following statements for the order of a reaction is incorrect?
Order of reaction can be zero, whole number, or fractional.
If x is amount of adsorbate and m is amount of adsorbent, which of the following relations is not related to adsorption process?
x/m = f(P) at constant T and
x/m = f(T) at constant T
Thus, it can be stated that for constant value of x/m, pressure and temperature can take different values or P = f(T) at constant (x/m).
But x/m ≠ P × T
Which of the following elements is present as the impurity to the maximum extent in the pig iron?
Pig iron or cast iron contains 3 – 5% carbon and varying amounts of Mn, Si, P and S which makes the iron hard and brittle.
Which of the following pairs of metals is purified by van Arkel method?
Zr and Ti are purified by van Arkel method.
Zr(s) + 2I₂(g) ⟶ ZrI₄(g)
ZrI₄(g) ── On the hot filament ──> Zr(s) + 2I₂(g)
For the four successive transition elements (Cr, Mn, Fe and Co), the stability of +2 oxidation state will be there in which of the following order?
.
Acidified K₂Cr₂O₇ solution turns green when Na₂SO₃ is added to it. This is due to the formation of:
The green colour appears due to the formation of Cr³⁺ ion
Cr₂O₇²⁻ + 3SO₃²⁻ + 8H⁺ ⟶ 3SO₄²⁻ + 2Cr³⁺ + 4H₂O
The complexes [Co(NH₃)₆][Cr(CN)₆] and [Cr(NH₃)₆][Co(CN)₆] are the examples of which type of isomerism?
Interchange of ligand between the complexes give isomers e.g. [Co(NH₃)₆] [Cr(CN)₆] is an isomer of [Co(CN)₆] [Cr(NH₃)₆]
The complex, [Pt(Py)(NH₃)BrCl] will have how many geometrical isomers?
Complexes of the type [M_ABCD] may exist in three isomeric forms.
Similarly, [Pt(Py)(NH₃)BrCl] may exist in three isomeric form in which
M = Pt, A = Py, B = NH₃, C = Br, D = Cl.
Of the following complex ions, which is diamagnetic in nature?
Ni²⁺ = 3d⁸ 4s⁰
Since, the coordination number of Ni in this complex is 4, the configuration of Ni²⁺ at first sight shows that the complex is paramagnetic with two unpaired electron. However, experiments show that the complex is diamagnetic. This is possible when the 3d electrons rearrange against the Hund's rule as shown below. This is in accordance with the fact that the ligand involved here is strong i.e., CN⁻ ion. Ni²⁺ (after rearrangement)
Hence, now dsp² hybridization involving one 3d, one 4s and two 4p orbitals, takes place leading to four dsp² hybrid orbitals, each of which accepts four electron pairs from CN⁻ ion forming [Ni(CN)₄]²⁻ ion.
[Ni(CN)₄]²⁻
Thus, the complex is diamagnetic as it has no unpaired electron.
The d-electron configurations of Cr²⁺, Mn²⁺, Fe²⁺ and Co²⁺ are d⁴, d⁵, d⁶ and d⁷ respectively. Which one of the following will exhibit minimum paramagnetic behaviour?
Minimum paramagnetic behaviour. =[Co(H₂O)₆]²⁺
Clemmensen reduction of a ketone is carried out in the presence of which of the following?
Clemmensen reduction is
In a set of reactions m-bromobenzoic acid gave a product D. Identify the product D.
Clemmensen reduction is
What is the product obtained in the following reaction:
When a nitro compound is reduced with a neutral reducing agent (Zn dust + NH₄Cl), the corresponding hydroxyl amine is formed.
Which one of the following statements is not true regarding (+) Lactose?
All reducing sugars shows mutarotation.
Of the following which one is classified as polyester polymer?
Polyesters are condensation polymers of a diabasic acid and a diol. e.g., Terylene.
Which one of the following is employed as Antihistamine?
Diphenyl hydramine, also known as Benadryl, is an antihistamine.
The half life of a substance in a certain enzyme-catalysed reaction is 138 s. The time required for the concentration of the substance to fall from 1.28 mg L⁻¹ to 0.04 mg L⁻¹ is:
For a first order reaction
Total time T = no. of half lives (n) × half life (t₁/₂)
N / N₀ = (1/2)ⁿ
where n = no. of half lives
Give N₀ (original amount) = 1.28 mg/l
N (amount of substance left after time T) = 0.04 mgL⁻¹
∴ 0.04 / 1.28 = (1/2)ⁿ ; 1 / 32 = (1/2)ⁿ ; (1/2)⁵ = (1/2)ⁿ
n = 5
T = 5 × 138 = 690
Mole fraction of the solute in a 1.00 molal aqueous solution is:
1.00 molal aqueous solution contain mole in 1000 g water
n_solute = 1 mol
w_solvent = 1000 g
n_solvent = 1000 / 18 = 55.56 mol
x_solute = 1 / (1 + 55.56) = 0.0177
Which one of the following animals is correctly matched with its particular named taxonomic category ?
Tiger and tigris both are from same genus with a
particular taxonomic category.
In eubacteria, a cellular component that resembles eukaryotic cells is:
Eubacteria are prokaryotic but eubacteria are
enclosed by plasma membrane like eukaryotic cells.
Organisms called methanogens are most abundant in a
Methanogens are archacbacteria, abundant in cattle
yard and paddy fields.
Methanogens produce methane as a metabolic byproduct in hypoxic conditions. They are prokaryotic and belong to the domain of archaea.
Which one of the following organisms is not an example of eukaryotic cells ?
E.coliis a prokaryotic gram negative bacterium
Archegoniophore is present in :
Archegoniophore is the female sex organ of bryophytes (Marchantia) and pteridophytes. Its neck
region is made up of 4-6 vertical rows of cells.
The gametophyte is not an independent, free living generation in :
Unlike bryophytes and pteridophytes, in gymnosperms the male and female gametophytes do not have an independent free-living existence. They remain with in the sporangia retained on the sporophytes.
Compared with the gametophytes of the bryophytes the gametophytes of vascular plant are
The gametophyte of ‘bryophytes are smaller but have large sex organs.
Which one of the following have the highest number of species in nature?
In nature insects have the highest number of species 1t (30 million). Fungi have 100,000, angiosperms have 260000 and birds have 10,000 species.
What will you look for to identify the sex of the following
A male shark possesses a pair of claspers which are inserted into a female shark’s cloaca (an opening on the underside of the body) at the time of mating. Claspers are located on the inner edge of the pelvic fins near the male's cloaca. The function of claspers is to introduce sperm into a female shark's body for the purpose of fertilizing her eggs. Female sharks do not have claspers.
Which one of the following groups of animals is correctly
matched with its one characteristic feature without even a
single exception?
Chondrichthyes are the cartilaginous fish with a flexible skeleton made of cartilage rather than bone.
In which one of the folllowing, the genus name, its two characters and its class/phylum are correctly matched?
The characteristics and phylum of Preropus is accurate.
Flowers are zygomorphic 1n
When a flower can be divided into two similar halves only in one particular vertical plane, it is zygomorphic, e.g.
pea, gulmohar, bean, etc.
‘Which one of the following statements is correct?
Tulips are most popular and wildly grown flowers.
Tulips are bulbs, possessing modified stems and leaves.
‘What would be the number of chromosomes of the aleurone cells of a plant with 42 chromosomes in its root tip cells?
Aleurone cells are the outer cell layer of the endo sperm, usually only one cell thick in wheat and the only endosperm tissue alive at maturity. The cell layers of this layer are responsible for the de-novo synthesis of enzyme needed during germination. The chromosome number is 63 of a plant with 42 chromosome in its root tip cells.
The correct floral formula of chilli is;
Floral formula of chilli is
The ovary is half inferior in flowers of
The ovary is half-inferior in flowers of peach.
Ground tissue includes
Ground tissue includes all tissues except epidermis and vascular bundles. The ground tissue comprises the -bulk of the primary plant body. Parenchyma, collenchyma and sclerenchyma cells are common in the ground tissue,
In land plants, the guard cells differ from other epidrmal cells in having :
Guard cells differ from epidermal cells in having chloroplast. The cell wall of guard cells are not uniform, -
inner walls are thicker than the outer walls, epidermal are uniformly thin.
‘Which one of the following is wrongly matched?
Smut is a disease of cereals, corn, grasses and
sorghum caused by many species of fungi.
The cork cambium, cork and secondary cortex are collectively called:
Phellem, phellogen and phelloderm are collectively called periderm.
The ciliated columnar epithelial cells in humans are known to occur in :
Ciliated epithelium is usually found in the respiratory tract and fallopian tubes. Ciliated epithelium is a thin tissue that has hair-like structures on it. These hairs, called cilia, move back and forth to help move particles out of our body. We find ciliated epithelial tissue in our respiratory tract and in the fallopian tubes of women. Ciliated epithelium performs the function of moving particles or fluid over the epithelial surface in such structures as the trachea, bronchial tubes, and nasal cavities. It often occurs in the vicinity of mucus-secreting goblet cells.
Which of the following is correctly stated as it happens It the common cockroach ?
Cockroach intake the food after grounding it by its
mandibles and gizzard.
One very special feature in the earthworm Pheretima is that.
The intestine of an earthworm has a peculiar fold of tissue that forms a pocket in the intestine that is visible when viewing a cross section. This space, which runs almost the whole length of the body dorsally, is known as the typhlosole and it serves to increase the surface area of the intestine for absorption.
. Important site for formation of glycoproteins and glycolipids is
Golgi apparatus is the important site for formation of glycoprotein and glycolipid
Peptide synthesis inside a cell takes place in:
Peptide synthesis takes place in ribosome of the cell.
What are those structures that appear as beads - on- string in he chromosomes when viewed under electron microscope?
Under electron microscope the nucleosomes appear as beads on a string in chromosome, due to a short length of DNA wrapped around a core of histone proteins.
Which one of the following structural formulae of two organic compounds is correctly identified along with its related finction?
Lecithin is a fat like substance (a phospholipid), which is a part of plasma membrane
The curve given below shows enzymatic activity with
relation to three conditions (pH, temperature and substrate
concentration.) What do the two axes (x and y) represent ?
In the given curve, the relation between temperature and enzyme activity is shown.
Select the correct option with respect to mitosis.
In mitosis, chromosomes move to the equator and get aligned along equatorial plate in metaphase
Which one of the following elements in plants is not re- ‘mobilised?
Calcium is not remobilized from the leaves to the fruits, like potassium, phosphorus and sulphur. It occurs abundantly in a non-exchangeable form such as anorthite (CaAl₂Si₂O₈).
A prokaryotic autotrophic nitrogen fixing symboint is found in
A prokaryotic autotrophic nitrogen fixing symbiont is found in Cycas.
Nitrifying bacteria :
The nitrifying bacteria bring about transformations of ammonia to nitrite and of nitrite to nitrate.
The function of leg haemoglobin in the root nodules of legumes is :
Leghaemoglobin is the haemoglobin like red pigment found in root nodules of legumes and reported to function as an oxygen-carrying pigment in symbiotic nitrogen fixation.
CAM helps the plants in
CAM plants are most common in arid environments.
Being able to keep stomata closed during the hottest and driest part of the day reduces the loss of water through evapotranspiration.
Two friends are eating together on a dining table. One of them suddenly starts coughing while swallowing some food. This coughing would have been due to improper ‘movement
The coughing would have been due to improper movement of epiglottis.
Which one of the following enzymes carries out the initial step in the digestion of milk in humans?
Rennin is an enzyme that is essential for the protein
digestion. It is active in acidic medium and inactive in
normal gastric juice of adult.
The figure given below shows a small part of human lung where exchange of gases takes place. In which one of the options given below, the one part A, B, C or D is correctly identified along with its function?
In the given figure the exchange of respiratory gases occurs in alveolar cavity.
A large proportion of oxygen is left unused in the human blood even after its uptake by the body tissues. This O₂
A large portion of oxygen is left unused in the human
‘blood even after its uptake by the body tissues. This O, acts as a reserve during muscular exercise.
Which one of the following plasma proteins is involved in the coagulation of blood?
Fibrinogen, the protein of blood plasma is converted into insoluble protein fibrin during the clotting process. The fibrinogen free fluid, obtained after removal of the clot, called blood serum, is plasma minus fibrinogen.
'Bundle of His' is a part of which one of the following organs in humans?
Bundle of His’ are a typical cardiac muscle fibres, connecting the atria with ventricle.
Arteries are best defined as'the vessels which :
Arteries are the vessels which break up into capillaries which reunite to form one visceral organ.
‘Which one of the following statements is correct regarding blood pressure ?
190/110 mmHg may harm vital organs like brain and kidney. This is called hypertension which can give rise to increased heart rate and palpitation.
Uricotelic mode of passing out nitrogenous wastes is found in
Organisms which excrete nitrogenous wastes in the form of urea are called ureotelic organisms whereas the organisms which excrete nitrogenous wastes in the form of uric acid are called uricotelic organisms. Uric acid is the least poisonous and the least soluble in water, relative to Ammonia and Urea.
Which one of the following is not a part of a renal pelvis?
Renal pelvis is the innermost portion of kidney. So, collecting ducts are not a part of renal pelvis.
Which one of following correctly explain function of a specific part of a human nephron ?
The pituitary gland is located in a bony cavity called sella tursica and is attached to hypothalamus by a stalk. It is divided anatomically into an adenohypophysis and a neurohypophysis. The Iatter is also called pars nervosa or posterior pituitary. The latter is also called pars nervosa or posterior pituitary. It stores and releases two hormone
called oxytocin and vasopressin, which are actually synthesized by the hypothalamus and are transported axonally to neurohypophysis. Vasopressin acts mainly at the kidney and stimulates resorption of water and electrolytes by the distal tubules in the nephron and
thereby reduced loss of water through urine (divresis). Hence, it is also called as anti-divretic hormone (ADH).
Which one of the following statement is correct with regard to kidney function regulation?
Podocytes are highly specialized cells with a complex
cytoarchitecture plays a major role in establishing the
selective permeability of glomerular filtration barrier.
When a neuron is in resting state i.e., not conducting any impulse, the axonal membrane is:
When some one drinks lots of water, kidney release of ADH is suppressed.
The purplish red pigment rhodopsin contained in the rods type of photoreceptor cells of the human eye, is a derivative of:
When a neuron is in resting state i.e., not conducting any impulse, the axonal membrane is comparatively more permeable to K⁺ ion and nearly impermeable to Na⁺ ions.
Match the source gland with respective hormone as well as the function correctly.
Rhodopsin contained in the rod type of photoreceptor cells of human eye is a derivative of vitamin A.
Given below is an incomplete table about certain hormones, their source glands and one major effect of each on the body in humans. Identify the correct option for the three blanks, A, B and C.
Anterior pituitary secretes growth hormone. Ovary secretes oestrogen hormone. Alpha cells of islets of Langerhans secrete glucagon.
The “Eyes” of the potato tuber are
The axillary buds of the potato tuber are called “eyes”
in common language. They are found at the nodes of the stem tuber.
Filiform apparatus is a characteristic feature of
A synergid cell wall forms a highly thickened structure called the filiform apparatus at the micropylar end consisting of numerous finger like projections into synergid cytoplasm. These synergid cells are necessary for pollen tube guidance in ovule.
In which one of the following pollination is autogamous?
Cleistogamy is autogamous pollination. When pollination and fertilization occur in unopened flower bud, it is known as cleistogamy. It ensures self-pollination and prevents crosspollination.
Wind pollination is common in
Wind pollination is common in grasses. Grasses produce large amount of pollen which by the help of wind reach to opposite sex for reproduction.
A drupe develops in
Some fleshy fruits such as mango, plum etc. usually have a single hard stone that encloses a seed, called drupe.
Nucellar polyembryony is reported in species of
Nucellar polyembryony is reported in a Citrus species.
If for some reason, the vasa efferentia in the human reproductive system gets blocked, the gametes will not be transported from
If the vasa efferentia in the human reproductive system get blocked the gametes will not be transformed from testes to epididymis.
The testes in humans are situated outside the abdominal cavity insides pouch called scrotum. The purpose served is for
The testes are present in the scrotum which maintains the scrotal temperature below 2°C of the internal body temperature.
The figure given below depicts a diagrammatic sectional view of the female reproductive system of humans. Which one set of three parts out of I-VI have been correctly identified?
In the given figure
III - marked portion is Infundibulum IV - marked portion is Fimbriae
V - marked portion is Cervix
Which one of the following is the most widely accepted method of ion in India, as at present ?
Intra uterine device (IUD) is a method of contraception in India. The IUD is inserted in the woman’s uterus through the cervix.
Medical Termination of Pregnancy (MTP) is considered safe up to how many weeks of pregnancy?
Medical termination of pregnancy is considered safe up to twelve weeks of pregnancy.
When two unrelated individuals or lines are crossed, the performance of F₁ hybrid is often superior to both parents. This phenomenon is called:
Heterosis or hybrid vigor occurs when two unrelated individuals or lines are crossed, the performance of F₁ hybrid, which is often superior to both the parents.
A person with unknown blood group under ABO system, has suffered much blood loss in an accident and needs im- mediate blood transfusion. His one friend who has a valid certificate of his own blood type offers blood donation without delay. What would have been the type of blood group of the donor friend?
TypeO
Which one of the following conditions correctly describes the manner of determining the sex in the given example?
XO type of sex chromosomes determine male sex in grasshopper
Mutations can be induced with :
Mutation can be induced by gamma radiation.
Given below is a sample of a portion of DNA strand. What is so special shown in it?
5' -----------GAATTC---------------3'
'3--------------- CTTAAG ------------ 5'
The sample of a portion of DNA strand shown in the figure is palindromic sequence of base pairs.
Which one of the following also acts as a catalyst in a bacterial cell ?
23S rRNA acts as a catalystina bammal cell.
What was the most significant trend in evolution of modermn ‘man (Homo sapiens) from his ancestors?
Increasing brain capacity
Where will you look for the sporozoites of the malarial parasite?
Saliva of infected female Anopheles mosquito
‘Which one of the following is categorised as a parasite in true sense ?
Headlouse is an obligate ectoparasite of human scalp and as well as laying egg on human hair.
‘Which one of the following acts as a physiological barrier to the entry of isms in human body?
Skin has a metabolic function to prevent non- resident bacteria from developing.
At which stage of HIV infection does one usually show symptoms of AIDS?
When HIV replicates rapidly in helper T- lymphocytes and damages large number of these
A certain patient is suspected to be suffering from Acquired Immuno Deficiency Syndrome. Which diagnostic technique will you recommend for its detection?
ELISA is an fundamental tool of clinical immunology and is used as an initial screen for HIV detection.
Jaya and Ratna developed for green revolution in India are the varieties of
rice
Himgiri developed by hybridisation and selection for disease resistance against rust pathogens is a variety of
‘Himgiri’ developed by hybridisation and selection for disease resistance against rust pathogens is a variety of wheat. It is resistant to leaf/stripe rust and hill bunt.
Ethanol is commercially produced through a particular species of :
Saccharomyces
Which one of the following help in absorption of phosphorus from soil by plants?
Glomus
Which one of the following is not a biofertilizer?
Agrobacterium
There is a restriction endonuclease called EcoRI. What does "co" part in it stand for?
EcoRI is an endonuclease enzyme isolated from strains of E.coli and a part of restriction modified system. So co part stands for coli.
A garose extracted from sea weeds finds use in:
Gel electrophoresis
The most common substrate used in distilleries for the production of ethanol is
molasses
The process of RNA interference has been used in the development of plants resistant to
RNA interference has been used to develop plants resistant to nematodes. RNA interference is a double stranded RNA (dsRNA) induced for gene sllencm, phenomenon
Continuous addition of sugars in ‘fed batch’ fermentation is done to:
purify enzymes
Maximum number of existing transgenic animals is of
In the world maximum number of existing transgenic animals is mice.
Large woody vines are more commonly found in:
tropical rainforests
Consider the following four conditions (i) - (iv) and select the correct pair of them as adaptation to environment in desert lizards.
(i) Burrowing in soil to escape high temperature
(ii) Losing heat rapidly from the body during high temperature
(iii) Bask in sun when temperature is low
(iv) Insulating body due to thick fatty dermis
Some species make permanent burrows deep into the soil to escape high temperature or sunlight and some cold blooded animals often like to bask in the sun to warm up their body.
Which one of the following statements is correct for secondary succession ?
Secondary succession refers to the regrowth of a habitat in the area where disruptive event has occurred and eliminated the existing, above ground plant life of the natural habitat. So, it occurs on a deforested site.
What type of human population is represented by the following age pyramid?
Declining population
Of the total incident solar radiation the proportion of PAR
Out of total incident solar radiation, about 50% ofi forms Photosynthetically Active Radiation (PAR).
Mass of living matter at a trophic level in an area at any time is called
A standing crop is the quantity or total weight or energy content of the organism, which are in a particular location at a particular time.
‘Which one of the following statements for pyramid of energy is incorrect, whereas the remaining three are correct
It is inverted in shape
Which one of the following shows maximum genetic diversity in India?
In India maximum genetic diversity is seen in rice. Total of 23 variety of irrigated ecology and 8 varieties of rainfed ecology has been invented in India.
A collection of plants and seeds having diverse alleles of all the genes of a crop is called
germplasm
Secondary sewage treatment is mainly a
biological process
Which of the following is mainly produced by the activity of anaerobic bacteria on sewage?
Marsh gas is another term for methanc produced by plants decomposmg under water.
Eutrophication is often seen in
fresh water lakes
Which one of the following statements is wrong in case of Bhopal tragedy?
The Bhopal gas tragedy occured on the night of December 2-3, 1984 at the Union carbide India Limited pesticide plant in Bhopal, M.P. A leak of methyl isocyanate gas and other chemicals from the plant resulted in the exposure of thousands of people.
Which one of the following expanded forms of the following acronyms is correct?
The correct acronym of IUCN is International Union for Conservation of Nature and Natural resources.
Which one of following pairs of gases are the major cause of "Greenhouse effect"?
CO₂ and N₂O are major green house gases
A drupe develops in :
Mango
In the following reactions,
In this case, dehydration is governed by Saytzeff's rule, according to which hydrogen is preferentially eliminated from the carbon atom with fewer number of hydrogen atoms i.e., poor becomes poorer. Thus, 2-methyl-but-2-ene is the major product.
This reaction is governed by Markownikoff's rule according to which when an unsymmetrical reagent e.g. HBr adds to an unsymmetrical alkene, then the negative part of the reagent is added to that carbon atom of the double bond which bears the least number of hydrogen atom. Thus, in above case 2-methyl-2-bromobutane will be the major product.
Force F on a particle moving in a straight line varies with distance d as shown in the figure. The work done on the particle during its displacement of 12 m is
Work done = area under F-d graph = [2 × (7 - 3)] + [1/2 × 2 × (12 - 7)] = 8 + 5 = 13J.
Symbolic representation of four logic gates are shown as Pick out which ones are for AND, NAND and NOT gates, respectively
(ii), (iv) and (iii)
The correct order of increasing bond length of C-H, C-O, C-C and C=C is:
The given compound is
The momentum of a photon of energy hv will be
hv/c is correct answer.
Which of the following compounds has the lowest melting point ?
Melting point of metal halides decreases as the sjze
of the halogen increases. The correct order is
CaF₂.>CaCl₂ >CaBr₂>CaI₂
The correct order of increasing bond length of C–H, C–O, C–C and C=C is:
Bond length order is
C–C < C=C < C–O < C–H
1.10A° 1.34A° 1.40A° 1.54A°
Which one is a nucleophilic substitution reaction among the following?
Nucleophilic substitution reactions are the most common reactions of alkyl halides.
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