Chemical Kinetics Class 12 MCQs Questions with Answers

1. If the rate of a reaction is expressed by, rate = A [A]² [B], the order of reaction will be:

2. The reaction 2 SO2 (g) + O2 (g) ⇌ SO3 (g) is carried out in 1 dm³ vessel and 2 dm³ vessel separately. The ratio of the reaction velocities will be:

3. Which among the following is a false statement?

4. In the rate equation, when the concentration of reactants is unity then the rate is equal to:

5. Which of the following is affected by catalyst?

6. The rate constant for the reaction 2N2O5 → 4NO2 + O2 is 3.0 × 10-5 sec-1. If the rate is 2.40 × 10-5 mol litre-1 sec-1, then the concentration of N2O5 (in mol litre-1) is:

7. The rate law for the chemical reaction, 2NO2Cl → 2NO2 + Cl2 is r = k[NO2Cl]. Which of the following is rate controlling step?

8. The decomposition of phosphine (PH3) on tungsten at low pressure is a first order reaction. It is because the-

9. A zero order reaction X →Product , with an initial concentration 0.02M has a half life of 10 min. if one starts with concentration 0.04M, then the half life is:

10. The rate constant of  zero-order reactions has the unit:

11. The rate of a reaction is primarily determined by the slowest step. This step is called:

12. For a chemical reaction A → B, it is found that the rate of the reaction quardruples when the concentration of A is doubled. The rate expression for the reaction is, rate = k [A]n where the value of n is:

13. In the Haber process for the manufacture of ammonia the following catalyst is used:

14. In the first order reaction the concentration of reactant decreases from 0.6 M to 0.3 M in 30 minutes. The time taken for the concentration to change from 0.1 M to 0.025 M:

15. The rate of reaction between two reactants A and B decreases by a factor of 4 if the concentration of reactant B is doubled. The order of this reaction with respect to the reactant B is:

16. A first order reaction is 50% completed in 1.26 × 1014 s. How much time would it take for 100% completion?

17. The half-life period of any first order reaction:

18. For a chemical reaction A→B, it is found that the rate of reaction doubles when the concentration of A is increased four times. The order of reaction is:

19. The rate of first order reaction is 0.04 mol L-1 s-1 at 10 sec. and 0.03 mol L-1 at 2C seconds after initiation of the reaction. t1/2 of reaction is:

20.  For a unimolecular reaction: