The CBSE Class 12 Chemistry exam requires precision and a thorough understanding of Chemical Kinetics. This article provides a set of CBSE Class 12 PYQs on Chemical Kinetics to help you understand the topic and improve your skills with the help of detailed solutions, ensuring conceptual clarity, which will help you in the CBSE Class 12 2026 exam.
Whether you're revising the basics or testing your knowledge, these Chemical Kinetics Class 12 Notes will serve as a valuable practice resource.
The CBSE Class 12 2026 exam is likely to continue on the same pattern as CBSE Class 12 2025. One of the best ways to improve your preparation is to practise CBSE Class 12 previous year questions (PYQs), which include a fair mix of questions from all topics.
Also Read
![]()
CBSE Class 12 PYQs on Chemical Kinetics
1.
Which among the following is a false statement?- Rate of zero order reaction is independent of initial concentration of reactant.
- Half-life of a zero order reaction is inversely proportional to the rate constant.
- Molecularity of a reaction may be zero.
- For a first order reaction, \( t_{1/2} = 0.693/k \).
2.
Which of the following is the slope of the first order reaction in the plot of ln[R] vs. time ?- +k
- $\frac{+k}{2.303}$
- –k
- $\frac{–k}{2.303}$
3.
Assertion (A): In a first order reaction, if the concentration of the reactant is doubled, its half-life is also doubled.
Reason (R): The half-life of a reaction does not depend upon the initial concentration of the reactant in a first order reaction.- (A) and (R) are true, and (R) is the correct explanation of (A).
- (A) and (R) are true, but (R) is not the correct explanation of (A).
- (A) is true, but (R) is false.
- (A) is false, but (R) is true.
4.
Which of the following represents the fraction of molecules with energies equal to or greater than E$_a$?- $\dfrac{E_a}{RT}$
- e$^{-E_a/RT}$
- e$^{+E_a/RT}$
- $+\dfrac{E_a}{RT}$
5.
In the Arrhenius equation \( k = Ae^{-E_a/RT} \), ‘A’ represents:- effective collisions \hspace{1cm}
- frequency factor
- fraction of collisions \hspace{1cm}
- threshold energy
6.
A plot between concentration of reactant [R] and time ‘t’ is shown below. Which of the given order of reaction is indicated by the graph?![concentration of reactant [R] and time](https://images.collegedunia.com/public/qa/images/content/2025_07_10/image_8b8de08b1752140122510.png)
- Third order
- Second order
- First order
- Zero order
7.
The value of rate constant for a pseudo first order reaction:- depends only on temperature.
- depends on the concentration of reactants present in small amount.
- depends on the concentration of reactants present in large excess.
- is not dependent on the concentration of reactants.
8.
The unit of rate and rate constant are the same for a:- First order reaction
- Second order reaction
- Zero order reaction
- Third order reaction
9.
The number of molecules that react with each other in an elementary reaction is a measure of the:- activation energy of the reaction
- stoichiometry of the reaction
- molecularity of the reaction
- order of the reaction
10.
Unit of rate constant ‘k’ for a second order reaction is:- s$^{-1}$
- mol L$^{-1}$ s$^{-1}$
- mol$^{-1}$ L s$^{-1}$
- mol$^{-2}$ L s$^{-1}$
11.
The activation energy (E$_a$) of a reaction can be determined from the slope of which of the following plots?- ln $k$ vs. T
- $\dfrac{\ln k}{T}$ vs. T
- ln $k$ vs. $\dfrac{1}{T}$
- $\dfrac{T}{\ln k}$ vs. $\dfrac{1}{T}$
12.
The number of molecules that react with each other in an elementary reaction is a measure of the :- activation energy of the reaction
- stoichiometry of the reaction
- molecularity of the reaction
- order of the reaction
13.
Assertion (A): Actinoids show wide range of oxidation states.
Reason (R): Actinoids are radioactive in nature.- Both Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of the Assertion (A).
- Both Assertion (A) and Reason (R) are true, but Reason (R) is not the correct explanation of the Assertion (A).
- Assertion (A) is true, but Reason (R) is false.
- Assertion (A) is false, but Reason (R) is true.
14.
Assertion (A): In a first order reaction, if the concentration of the reactant is doubled, its half-life is also doubled.
Reason (R): The half-life of a reaction does not depend upon the initial concentration of the reactant in a first order reaction.- Both Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of the Assertion (A).
- Both Assertion (A) and Reason (R) are true, but Reason (R) is not the correct explanation of the Assertion (A).
- Assertion (A) is true, but Reason (R) is false.
- Assertion (A) is false, but Reason (R) is true.
15.
Which among the following is a false statement ?- Rate of zero order reaction is independent of initial concentration of reactant.
- Half-life of a zero order reaction is inversely proportional to the rate constant.
- Molecularity of a reaction may be zero.
- For a first order reaction, $t_{1/2} = 0.693/k$.
Comments