NEET Chemistry Chemical Kinetics MCQs Set A

Question: The unit of rate constant and rate of reaction are same for

• a) First order
• b) Zero order
• c) Second order
• d) Third order

Answer: Zero order

Question:  For a reaction of the type  is equal to

• a)

  

• b)

  

• c)

  

• d)

  

Answer:

Question: For a gaseous reaction, the rate of reaction may be expressed in the units

• a) atm
• b) atm s
• c) atm/s
• d) atm/s²

Answer: atm/s

Question:   A gaseous reaction,   shows increase in pressure from 100 mm to 120 mm in 5 minutes. The rate of disappearance of A₂ is

• a) 4 mm min^–1 
• b) 8 mm min^–1
• c) 16 mm min^–1
• d) 2 mm min^–1

Answer:  8 mm min^–1

Question: Which of the following will react at the highest rate?

• a) 1 mol of A and 1 mol of B in a 1 L vessel
• b) 2 mol of A and 2 mol of B in a 2 L vessel
• c) 3 mol of A and 3 mol of B in a 3 L vessel
• d) All would react at the same rate

Answer: All would react at the same rate

Question: Which of the following does not affect the rate of reaction?

• a) Amount of the reactant taken
• b) Physical state of the reactant
• c) ΔH of reaction
• d) Size of vessel

Answer:  ΔH of reaction

Question:  In a reaction, 2X + Y → X₂ Y, the X disappears at

• a) Half the rate as that of disappearance of Y
• b) The same rate as that of disappearance of Y
• c) The same rate as that of appearance of X₂Y  
• d) Twice the rate as that of appearance of X₂Y

Answer:  Twice the rate as that of appearance of X₂Y

Question: During the course of a chemical reaction, the rate of a reaction

• a) Remains constant throughout
• b) Increases as the reaction proceeds
• c) Decreases as the reaction proceeds
• d) First increases followed by a decrease

Answer: Decreases as the reaction proceeds

Question: A reaction involving two different reactants can never be a

• a) Second order reaction
• b) Biomolecular reaction
• c) Unimolecular reaction
• d) First order reaction

Answer: Unimolecular reaction

Question:  For the hypothetical reaction 2A→ 3C, the reaction rate ‘r’ in terms of the rate of change of the concentration is given by

• a)

  

• b)

  

• c)

  

• d)

  

Answer:

Question:  In an experiment to study the reaction  at t = 0 was found to be 2.6×10^–2 M s^–1. What is the value of  at t = 0 in M s–¹ ?

• a) 2.6 × 10^–2
• b) 5.2 × 10^–2
• c) 1.3 × 10^–2
• d) 1.0 × 10^–1

Answer:  5.2 × 10^–2

Question:  For the reaction N₂+ 3H₂→2NH₃ , the rate of change of concentration for hydrogen is –0.3 × 10^–4 Ms^–1. The rate of change of concentration of ammonia is

• a) –0.2 × 10⁴
• b) 0.2 × 10^–4 
• c) 0.1 × 10^–4
• d) 0.3 × 10^–4

Answer:  0.2 × 10^–4 

Question:  The graph plotted between concentration versus time

• a) It gives rate of disappearance of reactant
• b)

  

• c) Both (1) & (2)
• d) It predicts the order of reaction

Answer: Both (1) & (2)

Question:  For reaction, 2B + A→ 2C

Which of the following is correct ?

• a) Rate of disappearance of B is twice that of rate of disappearance of C
• b) Rate of disappearance of A is twice that of rate of disappearance of C
• c) Rate of appearance of C is twice that of rate of disappearance of A
• d) All of these

Answer: Rate of appearance of C is twice that of rate of disappearance of A

Question:  For the homogeneous elementary reaction, A + B —→C, the unit of rate constant is

• a) s^–1
• b) s^–1 mol L^–1
• c) s^–1 mol^–1 L
• d) s

Answer:  s^–1 mol^–1 L

Question:   The rate law of a reaction between the substance A and B is given by, rate = k[A]ⁿ [B]^m. On doubling the concentration of A and making the volume of B half the ratio of new rate to the earlier rate of reaction will be

• a)

  

• b) m + n
• c) 2^{n + m}
• d) 2^{n – m}

Answer:  2^{n + m}

Question:  Consider the reaction, 2A + B —→ C + D. If the rate expression is r = [A]² [B]⁰ and if volume is reduced to 1/3 , the rate of reaction will increase

• a) 27 times
• b) 9 times
• c) 8 times
• d) Rate will not get affected

Answer: 9 times

Question: The rate constant is numerically the same for three reaction of first, second and third order respectively. Which one is true for rate of three reaction, if concentration of reactant is greater than 1M?

• a) r₁= r₂= r₃
• b) r₁> r₂> r₃ 
• c) r₁< r₂< r₃
• d) All of these

Answer:  r₁< r₂< r₃

Question:  Assuming an elementry reaction H₂O₂+ 3I^– + 2H⁺ —→ 2H₂O + I₃^–. The effect on the rate of this reaction brought about by doubling the concentration of I^– without changing the order

• a) The rate would increase by a factor of 3
• b) The rate would increase by a factor of 8
• c) The rate would decrease by a factor of 1/3
• d) The rate would increase by a factor of 9

Answer: The rate would increase by a factor of 8

Question:  For a reaction A + B → products, the rate of reaction was doubled when concentration of A was doubled. When concentration of A and B both was doubled, the rate was again doubled, order of reaction w.r.t. A and B are

• a) 1, 1
• b) 2, 0
• c) 1, 0
• d) 0, 1

Answer: 1, 0

Question: The overall order of reaction between X & Y is 3. Which of the following rate equation must be correct, if on doubling the concentration of X, the rate of reaction gets doubled ?

• a) r = K [X]² [Y]⁰
• b) r = K [X]¹ [Y]²
• c) r = K [X]¹ [Y]³ 
• d) r = K [X]² [Y]¹

Answer: r = K [X]¹ [Y]²

Question:  For a zero order reaction, K = 1 × 10^–3 mol L^–1 s^–1. If initial concentration of the reactant is 1.0 mol L^–1, the concentration after 10 minutes would be

• a) 1 × 10^–2 mol L^–1
• b) 0.6 mol L^–1
• c) 0.4 mol L^–1
• d) 1.0 mol L^–1

Answer:  0.4 mol L^–1

Question: Which of the following statement is not correct?

• a) Molecularity of a reaction cannot be fractional
• b) Molecularity of a reaction cannot be more than three
• c) Molecularity of a reaction may or may not be equal to the order of reaction
• d) Molecularity of a reaction can be obtained from balanced chemical equation

Answer: Molecularity of a reaction can be obtained from balanced chemical equation

Question: Consider the following in respect of zero order reaction

I. t_1/2 is directly proportional to the initial concentration

II. Time taken for the completion of the reaction is twice its t_1/2

III. Concentration of the reactant decreases linearly with time

Which of the statements given above are correct?

• a) I & II only
• b) I & III only
• c) II & III only
• d) I, II & III

Answer: I, II & III

Question:  If initial concentration is reduced to 1/4^th in a zero order reaction, the time taken for half the reaction to complete

• a) Remains same
• b) Becomes 4 times
• c) Becomes one-fourth
• d) Doubles

Answer: Becomes one-fourth

Question: If initial concentration of the reactants is doubled, the time for half reaction is also doubled, the order of the reaction is

• a) Zero
• b) One
• c) Two
• d) Three

Answer: Zero

Question:  The inversion of cane sugar represented by C₁₂H₂₂O₁₁+ H2O→ C₆H₁₂O₆+ C₂H₁₂O₆ is a _____ reaction.

• a) Unimolecular
• b) Second order
• c) Zero order
• d) First order

Answer: First order 

Question: For a Ist order reaction, a straight line is obtained if you plot

• a) Log conc. vs. time
• b) Conc. vs. time
• c) 1/conc. vs. time
• d) Log conc. vs. 1/time

Answer: Log conc. vs. time

Question:  Which order reaction obeys the expression ?

• a) First
• b) Second
• c) Third
• d) Zero

Answer: Second

Question:  The graph of t_½ versus initial concentration ‘a’ is for

• a) First order
• b) Second order
• c) Zero order
• d) Can’t predict

Answer: First order

Question: A substance (initial concentration 'a') reacts according to zero order kinetics. The time it takes for the completion of the reaction is

• a)

  

• b)

  

• c)

  

• d)

  

Answer:

Question: A first order reaction completes 60% in 20 minutes. The time required for the completion of 90% of the reaction is approx...

• a) 30 minutes
• b) 40 minutes
• c) 50 minutes
• d) 60 minutes

Answer: 50 minutes

Question: The half life period of a substance is 50 minutes at a certain initial concentration. When concentration is reduced to one-half, half life is found to 25 minutes. Order of reaction is

• a) Zero
• b) First
• c) Second
• d) Third

Answer: Zero

Question:  The half life of a second order process,

2A → products, is

• a) Independent of initial concentration
• b) Directly proportional to initial concentration of A
• c) Inversely proportional to initial concentration of A
• d) Inversely proportional to square of initial concentration

Answer: Inversely proportional to initial concentration of A

Question:  The rate constant for the forward and backward reactions of hydrolysis of ester are 1.1×10^–2 and 1.5×10^–3 min^–1 respectively. The equilibrium constant of the reaction is

• a) 7.33
• b) 0.733
• c) 73.3
• d) 733

Answer: 7.33

Question:   The rate law for the reaction,

RCl + NaOH(aq) → ROH + NaCl

is given by Rate = k[RCl]. The rate of reaction will be

• a) Doubled on doubling the concentration of NaOH
• b) Halved on reducing the concentration of alkyl halide to one-half
• c) Decreases on increasing the temperature
• d) Unaffected by increasing the temperature

Answer: Halved on reducing the concentration of alkyl halide to one-half

Question:  For a reaction, A —→ B, it has been found that the order of the reaction is zero with respect to A. Which of the following expressions correctly describes the reaction?

• a)

  

• b)

  

• c)

  

• d)

  

Answer:

Question:  A sample of a radioactive substance undergoes 80% decomposition in 345 minutes. Its half life is _____ minutes.

• a)

  

• b)

  

• c)

  

• d)

  

Answer:

Question: 99% of a first order reaction, was completed in 32 minute. When will 99.9% of the reaction complete?

• a) 50 minute
• b) 46 minute
• c) 49 minute
• d) 48 minute

Answer: 48 minute

Question: Check, which of the following statements is false?

• a) A catalyst does not differentiate between forward and backward reaction
• b) Large activation energy is associated with low reaction rate
• c) Maxwell's distribution of velocities remains-unaltered under all conditions of temperature and pressure
• d) A catalyst does not affect the equilibrium state of reaction

Answer: Maxwell's distribution of velocities remains-unaltered under all conditions of temperature and pressure

Question: Arrhenius parameter (A) depends on

• a) Steric factor
• b) Collision frequency
• c) Both (1) & (2)
• d) Neither (1) nor (2)

Answer: Both (1) & (2)

Question: The chemical reactions in which the reactants require high amount of activation energy are generally

• a) Slow
• b) Fast
• c) Instantaneous
• d) Spontaneous

Answer: Slow

Question:  For an exothermic chemical process occurring in two steps as

(i) A + B → X (slow) ; (ii) X → AB (fast)

The progress of the reaction can be best described by (X is considered as intermediate)

• a)

  

• b)

  

• c)

  

• d) None of these

Answer:

Question:  A chemical process occurring in two steps, is plotted as

The correct statement is

• a)

  

• b)

  

• c)

  

• d)

  

Answer:

Question:  For the chemical process energies are plotted in graph.

Which of the following is correct ?

• a) It is the exothermic reaction, ΔH = b – a 
• b) Threshold energy, e = a + c
• c)  (E_a)f< (E_a)_b 
• d) All of these

Answer: All of these

Question:  The rate of a reaction becomes 2 times for every 10°C rise in temperature. How many times rate of reaction will be increased when temperature is increased from 30°C to 80°C?

• a) 16
• b) 32
• c) 64
• d) 128

Answer: 32

Question: The rate of a reaction increases by 2.5 times when the temperature is raised from 300 K to 310 K. If K is the rate constant at 300 K, then the rate constant at 310 K will be equal to

• a) K
• b) 2K
• c) 2.5K
• d) 3K

Answer: 2.5K

Question: The minimum amount of energy that the reacting molecules must possess at the time of collisions in order to produce effective collision is called

• a) Activation energy
• b) Threshold energy
• c) Internal energy
• d) Free energy

Answer: Threshold energy

Question:  The rate constant, the activation energy and Arrhenius parameter of a chemical reaction at 25°C are x, 10xkJ/mol and 2x s^–1. Value of rate constant as T → ∞ is

• a) x s^–1 
• b) 2x s^–1
• c) ∞
• d) 10x s^–1

Answer:  2x s^–1

Question: At particular concentration, the half life of the reaction is 100 minutes. When the concentration of the reactant become double half life becomes, 25 minutes, then what will be the order of the reaction?

• a) 1
• b) 2
• c) 0
• d) 3

Answer: 3

Question:  Consider the data below for a reaction A →B

From the above data the order of reaction is

• a) Zero
• b) 1
• c) 2
• d) 3

Answer: Zero

Question: The graph between the log K versus 1/T is a straight line. The slope of the line is

• a)

  

• b)

  

• c)

  

• d)

  

Answer:

Question: The temperature coefficient for most of the reaction lies between

• a) 1 & 3
• b) 2 & 3
• c) 1 & 4
• d) 2 & 4

Answer: 2 & 3

Question:  If the volume of closed vessel in which the following simple reaction is carried out is reduced to one-third of original volume, the rate of reaction becomes

2NO (g) + O₂₍g) →2NO₂(g)

• a) One-third
• b) Three times
• c) Nine times
• d) Twenty seven times

Answer: Twenty seven times

Question:  For the reaction A + B → products, it is found that order of A is 2 and the order of B is 3 in the rate expression. When the concentrations of both A and B are doubled the rate will increase by a factor

• a) 10
• b) 16
• c) 32
• d) 28

Answer: 32

Question:  Nitric oxide (NO) reacts with oxygen to produce nitrogen dioxide

then rate law is

• a) Rate = K’ [NO][O₂]  
• b) Rate = K’ [NO][O₂]²
• c) Rate = K’ [NO]²[O₂]
• d) Rate = K’ [NO]³[O₂]

Answer:  Rate = K’ [NO]²[O₂]

Question: For a first order reaction, the time taken to reduce the initial concentration to a factor of 1/4 is 10 minute If the reduction in concentration is carried out to a factor of ,1/16 then time required will be

• a) 10 minutes
• b) 20 minutes
• c) 40 minutes
• d) 60 minutes

Answer: 20 minutes

Question:  For the reaction,

The relation between K₁, K₂ and K₃ is

• a) 2K₁= K₂= 4K₃ 
• b) K₁= K₂= K₃
• c) 2K₁= 4K₂= K₃ 
• d) K₁= 2K₂= 3K₃

Answer:  2K₁= K₂= 4K₃ 

Question:  For the reaction,

the rate of disappearance of NO₂ will be

• a) K₁[N₂O₄] – K₂[NO₂]² 
• b) 2K₁[N₂O₄] – 2K₂[NO₂]²
• c) K₂[NO₂]² – K₁[N₂O₄] 
• d) 2K₂[NO₂]² – 2K₁[N₂O₄]

Answer:   2K₂[NO₂]² – 2K₁[N₂O₄]

Question:  For a homogeneous gaseous reaction A→ B + C + D, the initial pressure was P₀ while pressure after time ‘t’ was P if (P > P₀). The expression for the rate constant K is

• a)

  

• b)

  

• c)

  

• d)

  

Answer: