Are these practice questions for Chemical Kinetics based on the CBSE pattern?

Yes. Every practice question is modeled on the CBSE Class 12 - Science Chemistry exam pattern — including MCQs, assertion-reason questions, and short-answer formats that frequently appear in CBSE papers.

Are the practice questions for Chemical Kinetics free?

Yes. Every chapter includes free practice questions for Class 12 - Science students to get you started.

What types of questions are included?

The practice set for Chemical Kinetics mainly includes MCQs and CBSE-style short-answer questions, with instant feedback on each answer. For full-length textbook practice, use the NCERT Solutions page.

Are the practice questions suitable for board exam preparation?

Yes. The questions test the same concepts and depth that CBSE asks in board exams. After finishing, also solve the NCERT and NCERT Exemplar exercises for Chemical Kinetics for full coverage.

How many practice questions are there for Chemical Kinetics?

The number scales with chapter length and concept density. Each chapter typically has 15-50 practice questions across MCQ and short-answer formats.

Chemical Kinetics Class 12 Chemistry Practice Questions with Answers

easy

Propose a justification for why elementary reactions with a molecularity greater than three are exceedingly rare.

Try solving it in your notebook first, then check the solution.

easy

Identify the key difference between an elementary reaction and a complex reaction.

Try solving it in your notebook first, then check the solution.

easy

Justify why the molecularity of a chemical reaction cannot be zero, a fraction, or a negative number.

Try solving it in your notebook first, then check the solution.

easy

Name two factors that influence the rate of a chemical reaction.

Try solving it in your notebook first, then check the solution.

easy

Define activation energy (

E_a

) and explain its role in a chemical reaction.

Try solving it in your notebook first, then check the solution.

easy

Define the instantaneous rate of a chemical reaction.

Try solving it in your notebook first, then check the solution.

easy

Examine the following rate constant value and identify the overall order of the reaction:

k = 3.5 \times 10^{-4} \text{ mol}^{-1} \text{ L s}^{-1}

.

Try solving it in your notebook first, then check the solution.

easy

List the units of the rate constant (k) for zero-order, first-order, and second-order reactions, assuming concentration is in

\text{mol L}^{-1}

and time is in seconds.

Try solving it in your notebook first, then check the solution.

easy

Recall the integrated rate equation for a first-order reaction.

Try solving it in your notebook first, then check the solution.

easy

A first-order reaction has a rate constant of

1.15 \times 10^{-3} \text{ s}^{-1}

. Calculate the half-life (

t_{1/2}

) of this reaction.

Try solving it in your notebook first, then check the solution.

easy

Compare how the half-life (

t_{1/2}

) of a reaction depends on the initial concentration of the reactant,

[R]_0

, for a zero-order reaction versus a first-order reaction.

Try solving it in your notebook first, then check the solution.

medium

For a zero-order reaction

R \rightarrow P

, demonstrate the derivation of the integrated rate equation. Also, analyze the graphical plot of reactant concentration

[R]

versus time

t

and state what the slope and intercept represent.

Try solving it in your notebook first, then check the solution.

medium

Recall the Arrhenius equation and name each variable in it.

Try solving it in your notebook first, then check the solution.

medium

For the reaction

2N_2O_5(g) \rightarrow 4NO_2(g) + O_2(g)

, the concentration of

N_2O_5

decreases from

1.20 \times 10^{-2} \text{ mol L}^{-1}

to

0.80 \times 10^{-2} \text{ mol L}^{-1}

in 10 minutes. Calculate the average rate of this reaction and the average rate of formation of

NO_2

during this interval.

Try solving it in your notebook first, then check the solution.

medium

A reaction has the rate law: Rate

= k[X]^2[Y]

. Analyze how the rate of reaction is affected if: (a) the concentration of Y is doubled, keeping X constant. (b) the concentrations of both X and Y are doubled.

Try solving it in your notebook first, then check the solution.

medium

Analyze the following experimental data for the reaction

A + 2B \rightarrow C

and determine the rate law and the overall order of the reaction.

Experiment	$[A] / \text{mol L}^{-1}$	$[B] / \text{mol L}^{-1}$	Initial Rate / $\text{mol L}^{-1}s^{-1}$
1	0.10	0.10	$2.0 \times 10^{-3}$
2	0.20	0.10	$4.0 \times 10^{-3}$
3	0.10	0.20	$8.0 \times 10^{-3}$

Try solving it in your notebook first, then check the solution.

medium

The hydrolysis of an ester like ethyl acetate in an acidic medium is technically a second-order reaction. Formulate the specific experimental conditions under which this reaction can be treated as a pseudo-first-order reaction and justify your reasoning.

Try solving it in your notebook first, then check the solution.

medium

For a first-order reaction, formulate a mathematical proof to show that the time required for

99.9\%

completion is approximately 10 times the half-life (

t_{1/2}

). Evaluate the practical significance of this finding.

Try solving it in your notebook first, then check the solution.

medium

Compare and contrast the molecularity and the order of a reaction by providing two distinct points of difference.

Try solving it in your notebook first, then check the solution.

medium

For the reaction

2N_2O_5(g) \rightarrow 4NO_2(g) + O_2(g)

, explain how the rate of reaction is expressed in terms of the change in concentration of each reactant and product.

Try solving it in your notebook first, then check the solution.

medium

Define the order of a reaction and identify the overall order for a reaction with the rate law: Rate

= k[A]^{3/2}[B]^{-1}

.

Try solving it in your notebook first, then check the solution.

medium

Critique the statement: 'For any chemical reaction, the order of reaction is always equal to the sum of the stoichiometric coefficients of the reactants in the balanced chemical equation.' Justify your position with an example.

Try solving it in your notebook first, then check the solution.

medium

A first-order reaction has a rate constant,

k = 5.5 \times 10^{-14} \text{ s}^{-1}

. Recall the formula and calculate the half-life of this reaction.

Try solving it in your notebook first, then check the solution.

medium

Propose a graphical method to distinguish between a zero-order and a first-order reaction. Describe the specific plots you would create from concentration versus time data and explain how the slope and intercept of each plot would confirm the reaction order.

Try solving it in your notebook first, then check the solution.

medium

Formulate the integrated rate law for a zero-order reaction

R \rightarrow P

and justify why its half-life depends on the initial concentration of the reactant, in contrast to a first-order reaction.

Try solving it in your notebook first, then check the solution.

medium

Explain the difference between the molecularity and the order of a reaction.

Try solving it in your notebook first, then check the solution.

medium

Examine the role of a catalyst in a chemical reaction by explaining its effect on the activation energy and the overall Gibbs free energy change (

\Delta G

) of the reaction.

Try solving it in your notebook first, then check the solution.

medium

A student proposes that the rate of decomposition of hydrogen peroxide,

2H_2O_2(aq) \rightarrow 2H_2O(l) + O_2(g)

, is second order with respect to

H_2O_2

because its stoichiometric coefficient is 2. Critique this reasoning and justify the correct approach to determine the order of this reaction.

Try solving it in your notebook first, then check the solution.

medium

Critique the Arrhenius equation,

k = A e^{-E_a/RT}

. While it effectively models the temperature dependence of the rate constant, what crucial physical aspect of a chemical reaction is represented implicitly by the pre-exponential factor, A, which is later made explicit by collision theory?

Try solving it in your notebook first, then check the solution.

medium

The hydrolysis of ethyl acetate (

CH_3COOC_2H_5

) in an aqueous solution is a second-order reaction, but it behaves as a pseudo-first-order reaction. Calculate the value of the pseudo-first-order rate constant if the true second-order rate constant is

2.0 \times 10^{-3} \text{ L mol}^{-1} \text{s}^{-1}

and the concentration of water is taken as a constant

55.5 \text{ mol L}^{-1}

.

Try solving it in your notebook first, then check the solution.

medium

Evaluate the limitations of the simple collision theory. Propose how the theory is modified to better align with experimental observations for reactions involving complex molecules.

Try solving it in your notebook first, then check the solution.

medium

Summarize the main points of the collision theory of chemical reactions.

Try solving it in your notebook first, then check the solution.

hard

Describe what is meant by a 'pseudo first-order reaction' and name an example.

Try solving it in your notebook first, then check the solution.

hard

Explain how a catalyst increases the rate of a reaction, using a potential energy diagram as a reference.

Try solving it in your notebook first, then check the solution.

hard

Analyze the following two-step mechanism for the decomposition of ozone: Step 1:

O_3(g) \rightleftharpoons O_2(g) + O(g)

(fast, equilibrium) Step 2:

O(g) + O_3(g) \rightarrow 2O_2(g)

(slow) From this mechanism, derive the rate law for the overall reaction

2O_3(g) \rightarrow 3O_2(g)

.

Try solving it in your notebook first, then check the solution.

hard

For a first-order reaction, the rate constant is

k = 4.606 \times 10^{-3} \text{ s}^{-1}

. If the initial concentration of the reactant is

1.0 \text{ mol L}^{-1}

, calculate: (a) The concentration of the reactant remaining after 100 s. (b) The time required for

75\%

of the reaction to be completed.

Try solving it in your notebook first, then check the solution.

hard

A first-order reaction is

40\%

complete in 50 minutes. Calculate the time it will take for the reaction to be

80\%

complete.

Try solving it in your notebook first, then check the solution.

hard

Design a series of experiments using the initial rates method to determine the rate law for the reaction:

A + 2B \rightarrow C

. Describe the data you would collect and formulate the process for analyzing this data to find the order with respect to A, the order with respect to B, and the overall rate constant

k

.

Try solving it in your notebook first, then check the solution.

hard

Design a plausible two-step reaction mechanism for the overall reaction

2A + B \rightarrow C + D

, given that the experimentally determined rate law is Rate

= k[A][B]

. Justify that your proposed mechanism is consistent with both the overall stoichiometry and the observed rate law.

Try solving it in your notebook first, then check the solution.

hard

The decomposition of ammonia on a hot platinum surface,

2NH_3(g) \xrightarrow{Pt} N_2(g) + 3H_2(g)

, is observed to be a zero-order reaction at high pressures. Create a conceptual model to justify this observation.

Try solving it in your notebook first, then check the solution.

hard

Propose a two-step mechanism for the reaction

2NO_2(g) + F_2(g) \rightarrow 2NO_2F(g)

, for which the experimentally determined rate law is Rate

= k[NO_2][F_2]

. Justify which step in your proposed mechanism is the rate-determining step.

Try solving it in your notebook first, then check the solution.

hard

The thermal decomposition of sulfuryl chloride (

SO_2Cl_2

) is a first-order gas-phase reaction:

SO_2Cl_2(g) \rightarrow SO_2(g) + Cl_2(g)

. At 600 K, the initial pressure of

SO_2Cl_2

in a closed container is

0.50

atm. After 100 seconds, the total pressure of the system is

0.60

atm. Calculate the rate constant (

k

) for this reaction.

Try solving it in your notebook first, then check the solution.

hard

The rate constant of a reaction is

1.5 \times 10^{-4} \text{ s}^{-1}

at

27^\circ\text{C}

and

3.0 \times 10^{-4} \text{ s}^{-1}

at

37^\circ\text{C}

. Calculate the activation energy (

E_a

) for this reaction. (Given:

R = 8.314 \text{ J K}^{-1} \text{mol}^{-1}

)

Try solving it in your notebook first, then check the solution.

hard

A chemical process has an activation energy

E_a = 80 \text{ kJ mol}^{-1}

. Evaluate whether it is more effective to increase its rate by increasing the temperature from

300 \text{ K}

to

310 \text{ K}

or by using a catalyst that lowers the activation energy by

20 \text{ kJ mol}^{-1}

at

300 \text{ K}

. Justify your conclusion quantitatively. (Use

R = 8.314 \text{ J K}^{-1} \text{mol}^{-1}

)

Try solving it in your notebook first, then check the solution.

Chemical KineticsClass 12 Chemistry Practice Questions