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NEET Chemical Kinetics: 5 practice MCQs with answers

By the PrepMatic team · Updated 9 Oct 2026 · 3 min read

Chemical Kinetics asks how fast a reaction goes and what controls its speed, and its questions are short, formula-based and usually quick to solve. The five MCQs below test the order from a rate law, a first-order half-life calculation, the units of the rate constant, and the effect of a catalyst, at NCERT Class 12 level.

What this chapter covers in the NEET syllabus

Chemical Kinetics is an NMC unit and a Class 12 NCERT chapter. The topics are:

• Rate of a reaction (average and instantaneous) and the factors that affect it.
• Rate law, rate constant, order and molecularity of a reaction.
• Integrated rate equations for zero-order and first-order reactions, and half-life.
• Collision theory in outline, the activation energy and the Arrhenius equation.
• The effect of temperature and of a catalyst on the rate.

Five practice MCQs on Chemical Kinetics

Question 1

For a reaction with rate = k[A]²[B], the overall order of the reaction is:

• A. 2
• B. 3
• C. 1
• D. 0

Question 2

A first-order reaction has a half-life of 20 minutes. The fraction of the reactant remaining after 60 minutes is:

• A. 1/3
• B. 1/6
• C. 1/8
• D. 1/16

Question 3

The unit of the rate constant for a second-order reaction is:

• A. s⁻¹
• B. mol L⁻¹ s⁻¹
• C. L² mol⁻² s⁻¹
• D. L mol⁻¹ s⁻¹

Question 4

A first-order reaction has a rate constant of 0.0693 min⁻¹. Its half-life is:

• A. 10 min
• B. 0.693 min
• C. 69.3 min
• D. 100 min

Question 5

A catalyst increases the rate of a reaction by:

• A. increasing the temperature of the reaction
• B. lowering the activation energy
• C. changing the enthalpy of reaction
• D. shifting the equilibrium position

Answers and explanations

1. B. The overall order is the sum of the powers in the rate law: 2 + 1 = 3. It is second order in A, first order in B, and third order overall. Order is found from experiments, not from the balanced equation.
2. C. 60 minutes is three half-lives (60/20). The fraction left is (1/2)³ = 1/8. Option A wrongly treats the decay as linear in time.
3. D. For an nth-order reaction, the unit of k is (mol L⁻¹)^(1−n) s⁻¹. With n = 2 this is L mol⁻¹ s⁻¹. Option A is the unit for first order, B for zero order and C for third order.
4. A. For first order t½ = 0.693/k = 0.693/0.0693 = 10 min. The half-life is independent of the initial concentration.
5. B. A catalyst provides an alternative path with a lower activation energy, so more molecules have enough energy to react. It does not change ΔH, and it does not change the equilibrium constant, because it speeds up the forward and backward reactions equally.

How to prepare Chemical Kinetics

• Keep zero-order and first-order results side by side. Zero order: rate = k, [A] = [A]₀ − kt, t½ = [A]₀/2k, unit of k mol L⁻¹ s⁻¹. First order: k = (2.303/t) log([A]₀/[A]), t½ = 0.693/k, unit s⁻¹. Memorise these two columns.
• Determine order from data. Compare two experiments in which only one concentration changes, and see how the rate changes. Practise a handful of such tables, since the same format is asked repeatedly.
• Separate order from molecularity. Order is experimental and can be zero or fractional. Molecularity applies to an elementary step and is a whole number (1, 2 or 3).
• Use half-life reasoning. Many first-order problems reduce to counting half-lives, as in Question 2, without any logarithm.
• Understand the Arrhenius equation qualitatively. k = A e^(−Ea/RT), so a lower Ea or a higher T gives a larger k. The log form is used for comparing rate constants at two temperatures.

Because the numericals are short, ten a day for a week is enough to make them routine. The NEET Chemistry preparation guide shows how physical chemistry fits in your plan, and the NEET syllabus lists every unit.

Take a full Chemical Kinetics test on PrepMatic

Kinetics numericals are short, so a timed test shows whether you can finish them quickly. Take a PrepMatic topic test (about 15 questions in 30 minutes), scored with NEET's negative marking. The free Basic plan includes topic tests, and the practice hub has more chapters.

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