FSc Part 1 Chemistry chapter 11: Reaction kinetics MCQs with answers

By Team Megalecture · Updated 4 Nov 2026

22 exam-style questions on Reaction kinetics, each with the answer and a short explanation. Ten of them are below to try. The chapter test draws ten fresh questions each time and is marked the moment you finish, with your score by topic.

22 questions · 2 topics · 10 per test

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What chapter 11 covers

Ten Reaction kinetics questions with answers

Try each one, then open the answer. These ten stay the same; the test draws new ones every time.

1. The rate equation of a reaction is rate = k[A]2[B]. What is the overall order of the reaction?

  1. A
    first
  2. B
    second
  3. C
    third
  4. D
    fourth
Show answer

Answer: C. The overall order is the sum of the powers in the rate equation: 2 + 1 = 3. The order is found by experiment, not from the balanced equation.

2. What are the units of the rate constant k for a second-order reaction?

  1. A
    s−1
  2. B
    dm3 mol−1 s−1
  3. C
    mol dm−3 s−1
  4. D
    dm6 mol−2 s−1
Show answer

Answer: B. k = rate ÷ [A]2 = (mol dm−3 s−1) ÷ (mol dm−3)2 = dm3 mol−1 s−1. s−1 is first order and dm6 mol−2 s−1 is third order.

3. The rate of a reaction in which a coloured reactant is used up is most conveniently followed by

  1. A
    dilatometry
  2. B
    spectrometry, measuring the absorption of light
  3. C
    measuring the electrical conductivity
  4. D
    measuring the optical rotation
Show answer

Answer: B. As the coloured reactant is used up, its light absorption falls in proportion to its concentration. Dilatometry follows volume changes and conductivity follows changes in ions.

4. The photochemical reaction between hydrogen and chlorine is zero order. This means that its rate

  1. A
    is zero
  2. B
    does not depend on the concentrations of the reactants
  3. C
    doubles when the concentrations are doubled
  4. D
    depends only on the concentration of chlorine
Show answer

Answer: B. rate = k[H2]0[Cl2]0 = k: the rate is controlled by the light intensity, not by the concentrations. The reaction does still happen.

5. The hydrolysis of ethyl acetate in a large excess of water, catalysed by acid, behaves as first order. It is called a pseudo-first-order reaction because

  1. A
    water is not a reactant
  2. B
    the reaction has two steps
  3. C
    the concentration of water hardly changes, so the rate depends only on the ester
  4. D
    the acid is used up
Show answer

Answer: C. Water is a reactant, but it is in such excess that its concentration stays almost constant and is absorbed into k. The acid catalyst is not used up.

6. In the Contact process, traces of arsenic(III) oxide stop the platinum catalyst from working. This is known as

  1. A
    promotion of the catalyst
  2. B
    autocatalysis
  3. C
    catalytic poisoning
  4. D
    negative catalysis
Show answer

Answer: C. As2O3 is adsorbed on the active sites of platinum and blocks them, poisoning the catalyst. This is one reason V2O5 is preferred today.

7. A rise of 10 K roughly doubles the rate of many reactions. What is the main reason?

  1. A
    the number of collisions per second doubles
  2. B
    the activation energy is halved
  3. C
    the fraction of molecules with energy equal to or greater than Ea increases greatly
  4. D
    the reaction becomes more exothermic
Show answer

Answer: C. A small rise in temperature greatly increases the number of molecules in the high-energy tail of the distribution. The collision frequency rises by only a few percent.

8. Nickel is used as a catalyst in the hydrogenation of vegetable oils to make ghee. This is an example of

  1. A
    homogeneous catalysis
  2. B
    heterogeneous catalysis
  3. C
    autocatalysis
  4. D
    negative catalysis
Show answer

Answer: B. The solid nickel is in a different phase from the liquid oil and hydrogen gas, so the catalysis is heterogeneous; reaction takes place on the metal surface.

9. When the initial concentration of a reactant is doubled, the half-life of the reaction is halved. What is the order of the reaction?

  1. A
    zero
  2. B
    first
  3. C
    second
  4. D
    third
Show answer

Answer: C. t½ ∝ 1/an−1. Halving t½ when a doubles means n − 1 = 1, so n = 2. For first order t½ would not change.

10. According to the Arrhenius equation, a graph of ln k against 1/T is a straight line. What does its slope equal?

  1. A
    −Ea/R
  2. B
    Ea/R
  3. C
    ln A
  4. D
    −R/Ea
Show answer

Answer: A. ln k = ln A − Ea/RT, so the slope is −Ea/R and the intercept is ln A.

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Reaction kinetics: questions students ask

How many Reaction kinetics MCQs are there?

22, each with the answer and a short explanation, across 2 topics: Rate of reaction, order and half-life, Activation energy, factors affecting rate and catalysis. Every chapter test draws ten of them, so you can take it many times.

Is the FSc Part 1 Chemistry chapter 11 test free?

Yes. The test, the answers and the explanations are free and need no sign-up. Sign in only if you want your scores kept across devices.

How is the chapter test marked?

The moment you press Finish: your score, the right answer and an explanation for every question, and the ones you got wrong saved in My mistakes to retry.

Can I read the explanations in Urdu?

Yes. In practice mode and on your results you can switch the explanations to Urdu.

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