CBSE EXAMINATION PAPER-2018
NEET-CHEMISTRY
(Solved)
General Instructions :
Read the following instructions carefully and follow them :
- This question paper contains 180 questions. All questions are compulsory.
- This question paper is divided into 1 sections.
- Section A – questions number 1 to 180 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 student measured the diameter of a small steel ball using a screw gauge of least count 0.001 cm. The main scale reading is 5 mm and zero of circular scale division coincides with 25 divisions above the reference level. If screw gauge has a zero error of –0.004 cm, the diameter of ball is
The moment of force on a force, 𝐅⃗ = 4î+ 5ĵ – 6k̂ at (2, 0, –3), about the point
(2, –2, –2), is given by
A block of mass m is placed on a smooth inclined wedge ABC of inclination θ as shown in the figure. The wedge is given an acceleration a towards the right. The relation between a and θ for the block to remain stationary on the wedge is
A moving block having mass m₁ collides with another stationary block having mass 4m. The lighter block comes to rest after collision. When the initial velocity of lighter block is v, then the value of coefficient of restitution (e) will be
A solid sphere is rotating freely about its symmetry axis in free space. The radius of the sphere is increased keeping its mass same. Which of the following physical quantities would remain constant for the sphere?
A solid sphere is in rolling motion. In rolling motion a body possesses translational kinetic energy (Kₜ) as well as rotational kinetic energy (Kᵣ) simultaneously. The ratio Kₜ : (Kₜ + Kᵣ)) for the sphere is
Three objects A (a solid sphere), B (a thin circular disk) and C (a circular ring), each have the same mass M and radius R. They all spin with the same angular speed ω about their own symmetry axes. The amount of work (W) required to bring them to rest, would satisfy the relation
The kinetic energies of a planet in an elliptical orbit about the Sun, at positions A, B and C are K_A , K_B, and K_C respectively. AC is the major axis and SB is perpendicular to AC at the position of the Sun S as shown in the figure. Then
Two wires are made of the same material and have the same volume. The first wire has cross-sectional area A and the second wire has cross-sectional area 3A. If the length of the first wire is increased by Δl on applying a force F, how much force is needed to stretch the second 'wire by the same amount?
A small sphere of radius ‘r’ falls from rest in a viscous liquid. As a result, heat is produced due to viscous force. The rate of production of heat when the sphere attains its terminal velocity, is proportional to
The power radiated by a black body is P and it radiates maximum energy at wavelength,λ₀ If the temperature of the black body is now changed so that it radiates maximum energy at wavelength 3/4 λ₀ ,the power radiated by it becomes nP. The value of n is
The volume (V) of a monatomic gas varies with its temperature (T), as shown in the graph. The ratio of work done by the gas, to the heat absorbed by it, when it undergoes a change from state A to state B, is
The efficiency of an ideal heat engine working between the freezing point and boiling point of water, is
At what temperature will the rms speed of oxygen molecules become just sufficient for escaping from the Earth’s atmosphere?
(Given:
Mass of oxygen molecule (m)=2.76 x 10⁻²⁶kg
Boltzmann’s constant k_B = 1.38 x 10⁻²³ JK⁻¹)
A pendulum is hung from the roof of a sufficiently high building and is moving freely to and fro like a simple harmonic oscillator. The acceleration of the bob of the pendulum is 20 m/s² at a distance of 5 m from the mean position. The time period of oscillation is
A tuning fork is used to produce resonance in a glass tube. The length of the air column in this tube can be adjusted by a variable piston. At room temperature of 27°C two successive resonances are produced at 20 cm and 73 cm of column length. If the frequency of the tuning fork 320 Hz, the velocity of sound in air at 27°C is
The fundamental frequency in an open organ pipe is equal to the third harmonic of a closed organ pipe. If the length of the closed organ pipe is 20 cm, the length of the open organ pipe is
An electron falls from rest through a vertical distance h in a uniform and vertically upward directed electric field E. ‘The direction of electric field is now reversed, keeping its magnitude the same. A proton is allowed to fall from rest in it through the same vertical distance h. The time of fall of the electron, in comparison to the time of fall of the proton is
A toy car with charge q moves on a frictionless horizontal plane surface under the influence of a uniform electric field 𝐄⃗ . Due to the force q 𝐄⃗ , its velocity increases from 0 to 6 m/s in one second duration. At that instant the direction of the field is reversed. The car continues to move for two more seconds under the influence of this field. The average velocity and the average speed of the toy car between 0 to 3 seconds are respectively
The electrostatic force between the metal plates of an isolated parallel plate capacitor C having a charge Q and area A, is
A carbon resistor of (47 ±4.7) kΩ is to be marked With rings of different colours for its identification. The colour code sequence will be
A set of 'n' equal resistors, of value 'R’ each, are connect in series to a battery of emf 'E' and internal resistance 'R' The current drawn is I. Now, the 'n' resistors are connected in parallel to the same battery. Then the current d from battery becomes 10 1. The value of 'n' is
A metallic rod of mass per unit length 0.5 kg m⁻¹ is horizontally on a smooth inclined plane which makes an angle of 30⁰ with the horizontal. The rod is not allowed to ide down by flowing a current through it when a magnetic field of induction 0.25 T is acting on it in the vertical direction. The current flowing in the rod to keep it stationary is
Current sensitivity of a moving coil galvanometer is 5 div/ mA and its voltage sensitivity (angular deflection per unit voltage applied) is 20 div/V. The resistance of the galvanometer is
A thin diamagnetic rod is placed vertically between the poles of an electromagnet. When the current in the electromagnet is switched on, then the diamagnetic rod is pushed up, out of the horizontal magnetic field. Hence the rod gains gravitational potential energy. The work required to do this comes from
The magnetic potential energy stored in a certain inductor is 25 mJ, when the current in the inductor is 60 mA. This inductor is of inductance
An inductor 20 mH, a capacitor 100 μFanda resistor 50Ω are connected in series across a source of emf, V.= 10 sin 314 t. The power loss in the circuit is
An em wave is propagating in a medium with a velocity 𝐕⃗ = 𝐕î . The instantaneous oscillating electric field of this em wave is along +y axis. Then the direction of oscillating ‘magnetic field of the em wave will be along
The refractive index of the material of a prism is √2 and the angle of the prism is 30°.One of the two refracting surfaces of the prism is made a mirror inwards, by silver coating. A beam of monochromatic light entering the prism from the other face will retrace its path (after reflection from the silvered surface) if its angle of incidence on the prism is
An astronomical refracting telescope will have large angular magnification and high angular resolution, when it has an objective lens of
In Young's double slit experiment the separation d between the slits is 2 mm, the wavelength λ of the light used is 5896 Å and distance D between the screen and slits is 100 cm. It is found that the angular width of the fringes is 0.20°. To increase the fringe angular width to 0.21° (with same λ and D) the separation between the slits needs to be changed to
Unpolarised light is incident from air on a plane surface of a material of refractive index 'μ'. At a particular angle of incidence 'i', it is found that the reflected and refracted rays are perpendicular to each other. Which of the: following options is correct for this situation?
An electron of mass m₀ with an initial velocity 𝐕⃗ = v₀ î (v₀ > 0) enters an electric field 𝐄⃗ = −E₀ î (E₀ = constant > 0) at t = 0. If λ₀ is its de-Broglie wavelength at t = 0, then its de-Broglie wavelength after time t is
The ratio of kinetic energy to the total energy of an electron in a Bohr orbit of the hydrogen atom, is
For a radioactive material, half-life is 10 minutes. If initially there are 600 number of nuclei, the time taken (in minutes) for the disintegration of 450 nuclei is
In ap-n junction diode, change in temperature due to heating
In the circuit shown in the figure, the input voltage Vᵢ is 20 V, V_BE = 0 and V_CE) = 0. The values of Iᵦ, I𝒸 and β are given by
In the combination of the following gates the output Y can be written in terms of inputs A and B as
A battery consists of a variable number 'n' of identical cells (having internal resistance 'r' each) which are connected in series. The terminals of the battery are short-circuited and the current I is measured. Which of the graphs shows the correct relationship between I and n?
An object is placed at a distance of 40 cm from a concave mirror of focal length 15 cm. If the object is displaced through a distance of 20 cm towards the mirror, the displacement of the image will be
‘When the light of frequency 2v₀ (where v₀ is threshold frequency), is incident on a metal plate, the maximum velocity of electrons emitted is v₁. When the frequency of the incident radiation is increased to 5v₀, the maximum velocity of electrons emitted from the same plate is v₂. The ratio of v₁ to v₂ is’
If the mass of the Sun were ten times smaller and th universal gravitational constant were ten times larger magnitude, which of the following is not correct?
A sample of 0.1 g of water at 100°C and normal pressure (1.013 x 10⁵Nm⁻²) requires 54 cal of heat energy to convert to steam at 100°C. If the volume of the steam produced is 167 . 1 cc, the change in internal energy of the sample , is
A body initially at rest and sliding along a frictionless track from a height h (as shown in the figure) just complete a vertical circle of diameter AB=D. The height h is equal
to
In which case is number of molecules of water maximum?
A mixture of 2.3 g formic acid and 4.5 g oxalic acid is treated with conc. H₂SO₄. The evolved gaseous mixture is passed through KOH pellets. Weight (in g) of the remaining product at STP will be
Which one is a wrong statement?
The correct order of atomic radii in group 13 elements is
In the structure of CIF₃, the number of lone pair of electron on central atom ‘Cl’ is
Which of the following molecules represents the order of hybridisation sp², sp², sp, sp from left to right atoms?
Consider the following species
CN⁺, CN⁻, NO and CN
‘Which one of these will have the highest bond order?
The correction factor ‘a’ to the ideal gas equation corresponds to
Given van der Waals constants for NH₃, H₂, O₂ and CO₂ are respectively 4.17, 0.244, 1.36 and 3.59, which one of the following gases is most easily liquefied?
The bond dissociation energies of X₂, Y₂ and XY are in the ratio of 1 : 0.5 : 1. ΔH for the formation of XY is −200 kJ mol⁻¹. The bond dissociation energy of X₂ will be :
‘Which one of the following conditions will favour maximum formation of the product in the reaction,
A₂(g) + B₂(g) ⇌ X₂(g) ΔᵣH = −X kJ;
Following solutions were prepared by mixing different volumes of NaOH and HCl of different concentrations :
a- 60 mL M/10 HCl + 40 mL M/10 NaOH
b-55 mL M/10 HCl + 45 mL M/10 NaOH
c-75 mL M/5 HCl + 25 mL M/5 NaOH
d- 100 mL M/10 HCl + 100 mL M/10 NaOH
pH of which one of them will be equal to 1?
The solubility of BaSO₄ in water is 2.42 × 10⁻³ gL⁻¹ at 298 K. The value of its solubility product (Kₛₚ) will be
(Given molar mass of BaSO₄ = 233 g mol⁻¹)
For the redox reaction
MnO₄⁻ + C₂O₄²⁻ + H⁺ → Mn²⁺ + CO₂ + H₂O
The correct coefficients of the reactants for the balanced equation are
Consider the change in oxidation state of bromine corresponding to different emf values as shown in the
diagram below :
Then the species undergoing disproportion-ation is
Which of the following oxides is most acidic in nature?
Among CaH₂, BeH₂, BaH₂, the order of ‘ionic character is
‘Which one of the following elements is unable to form
MF³₆⁻ ion?
‘Which of the following is correct with respect to — I effect
of the substituents? (R = alkyl)
Hydrocarbon (A) reacts with bromine by substitution to form an alkyl bromide which by Wurtz reaction is converted to gaseous hydrocarbon containing less than four carbon
atoms. (A) is
Which oxide of nitrogen is not a common pollutant introduced into the atmosphere both due to natural and
‘human activity?
Iron exhibits bcc structure at room temperature. Above 900°C, it transforms to fcc structure. The ratio of density of iron at room temperature to that at 900°C (assuming molar mass and atomic radii of iron remains constant with temperature) is
The correct difference between first and second order reactions is that
‘When initial concentration of the reactant is doubled, the half-life period of a zero order reaction
On which of the following properties does the coagulating power of an ion depend?
Considering Ellingham diagram, which of the following metals can be used to reduce alumina?
The correct order of N-compounds in its decreasing order of oxidation states is
‘Which one of the following ions exhibits d-d transition and paramagnetism as well?
The type of isomerism shown by the complex [CoCl₂(en)₂] is
The geometry and magnetic behaviour of the complex [Ni(CO)₄] are
Match the metal ions given in Column I with the spin magnetic moments of the ions given in Column II and assign the correct code :
Iron carbonyl, [Fe(CO)₅] is
The compound C₇H₈ undergoes the following reactions:
The product 'C' is
The compound A on treatment with Na gives B, and with PCl₅ gives C. B and C react together to give diethyl ether. A, B and C are in the order
Carboxylic acids have higher boiling points than aldehydes, ketones and even alcohols of comparable molecular mass. It is due to their
Nitration of aniline in strong acidic medium also gives mnitroaniline because
‘Which of the following compounds can form a zwitterion?
Regarding cross-linked or network polymers, which of the following statements is incorrect?
The difference between amylose and amylopectin is
Which of the following oxides is most acidic in nature?
Which of the following has proved helpful in preserving pollen as fossils?
Which among the following is not a prokaryote?
which of the following organisms are know as chief producers in the oceans?
Ciliates differ from all other protozoans in
Which one is wrongly matched?
After karyogamy followed by meiosis, spores are produced exogenously in
Select the wrong statement :
Which of the following animals does not undergo metamorphosis?
Pneumatophores occur in
Winged pollen grains are present in
Casparian strips occur in
Secondary xylem and phloem in dicot stem are produced by
Plants having little or no secondary growth are
The two functional groups characteristic of sugars are
The stage during which separation of the paired homologous chromosomes begins is
Stomatal movement is not affected by
Stomata in grass leaf are
In which of the following forms is iron absorbed by plant?
Which of the following elements is responsible for maintaining turgor in cells?
Oxygen is not produced by photosynthesis by
Which of the following is not a product of light reaction of photosynthesis?
What is the role of NAD⁺ in cellular respiration?
Which of the following terms describe human dentition?
Match the items given in Column I with those in Column ll and select the correct option given below:
Which part of poppy plant is-used to obtain the drug “Smack''?
Which of the following is an occupational respiratory disorder?
Match the items given in Column I with those in Column T and
select the correct option given below:
Match the items given in Column I with those in Column Il and
select the correct option given below:
Match the items given in Column I with those in Column I and
select the correct option given below:
Calcium is important in skeletal muscle contraction because it
‘Which of the following is not an autoimmune disease ?
Which of the following hormones can play a significant role in osteoporosis?
Which of the following structures or regions is incorrectly paired with its functions?
Nissl bodies are mainly composed of
The transparent lens in the human eye is held in its place by
Which of the following is an amino acid derived hormone?
Offsets are produced by
Which of the following flowers blooms only once in its life-time?
Pollen grains can be stored for several years in liquid nitrogen having a temperature of
Double fertilization is
The difference between spermiogenesis and spermiation is
Match the items given in Column I with those in Column Il and
select the correct option given below:
The amnion of mammalian embryo is derived from
Hormones secreted by the placenta to maintain pregnancy are
The contraceptive ‘SAHELI’
A woman has an X-linked condition on one of her X chromosomes. This chromosome can be inherited by
AGGTATGCCAT is a sequence from the coding strand of a gene. What will be the corresponding sequence of the transcribed mRNA?
Select the correct match
The experimental proof for semiconservative replication of DNA was first shown in a
All of the following are part of an operon except
According to Hugo de Vries, the mechanism of evolution is
Which of the following is commonly used as a vector for introducing a DNA fragment in human lymphocytes?
The correct order of steps in Polymerase Chain Reaction (PCR) is
Use of bioresources by multinational companies and organisations without authorisation from the concerned country and its people is called
In India, the organisation responsible for assessing the safety of introducing genetically modified organisms for public use is
A ‘new’ variety of rice was patented by a foreign company, though such varieties have been present in India for a long time. This is related to
Which one of these animals is not a homeotherm?
Match Column-1 with Column-II
In a growing population of a country,
Which one of the following population interactions is widely used in medical science for the production of antibiotics?
Which one of the following plants shows a very close relationship with a species of moth, where none of the two can complete its life cycle without the other?
World Ozone Day is celebrated on
Niche is
What type of ecological pyramid would be obtained with the following data?
Secondary consumer : 120 g
Primary consumer : 60 g
Primary producer : 10 g
All of the following are included in ‘ex-situ conservation” except
Which of the following is a secondary pollutant ?
Match the items given in Column I with those in Column II and select the correct option given below:
In stratosphere, which of the following elements acts as a catalyst in degradation of ozone and release of molecular oxygen?
Which of the following options correctly represents the lung conditions in asthma and emphysema, respectively?
Select the incorrect match:
Many ribosomes may associate with a single mRNA to form multiple copies of a polypeptide simultaneously. Such strings of ribosomes are termed as
Which of the following events does not occur in rough endoplasmic reticulum?
Identify the vertebrate group of animals characterized by crop and gizzard in its digestive system
Which of the following features is used to identify a male cockroach from a female cockroach?
Match the items given in Column I with those in Column II and select the correct option given below:
The Golgi complex participates in
Which of the following is true for nucleolus?
Select the correct match
Which of the following pairs is wrongly matched?
Natality refers to
Match the items given in Column I with those in Column II and select the correct option given below:
Which of the following statements is correct?
Sweet potato is a modified
Conversion of milk to curd improves its nutritional value by increasing the amount of
Which of the following gastric cells indirectly help in erythropoiesis?
In the reaction .
The electrophile involved is
Which one of the following statements is incorrect?
Which of the following statements is not true for halogens?
Which of these statements is incorrect?
Which of the following characteristics represent Inheritance of blood groups’ in humans?
A. Dominance
B. Co-dominance
C. Multiple allele
D. Incomplete dominance
E. Polygenic inheritance
Which of the following carbocations is expected to be most. stable?
Compound A, C₈H₁₀O, is found to react with NaOI (produced by reacting Y with NaOH) and yields a yellow precipitate with characteristic smell.
A and Y are respectively
Identify the major products P, Q and R in the following sequence of reactions:
Among the following sets of examples for divergent evolution, select the incorrect option:
The similarity of bone structure in the forelimbs of many vertebrates is an example of
In which disease does ‘mosquito transmitted pathogen cause chronic inflammation of Iymphatic vessels?