Chemical Kinetics MCQs

Analytical chemistry utilizes reactions to identify chemical compounds. Chemical thermodynamics examines chemical equilibrium as a source of work and heat, among other aspects. Kinetics, with its unique approach to chemical reactions, studies chemical transformations as processes that occur over time, following specific mechanisms and regularities characteristic of these processes. In the study of kinetics within chemical processes, the focus is on the rate of reactions, changes in these rates as the process progresses, and the overall temporal dynamics of the reactions.

Which of the following observations is incorrect about the order of a reaction?

(a) Order of a reaction is always a whole number
(b) The stoichiometric coefficient of the reactants doesn’t affect the order
(c) Order of reaction is the sum of power to express the rate of reaction to the concentration terms of the reactants.
(d) Order can only be assessed experimentally

The rate of a chemical reaction tells us about

(a) the reactants taking part in the reaction
(b) the products formed in the reaction
(c) how slow or fast the reaction is taking place
(d) none of the above

In the reaction 2A + B → A₂B, if the concentration of A is doubled and that of B is halved, then the rate of the reaction will

(a) increase 2 times
(b) increase 4 times
(c) decrease 2 times
(d) remain the same

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

(a) specific rate constant
(b) average rate constant
(c) instantaneous rate constant
(d) None of the above

A catalyst alters, which of the following in a chemical reaction?

(a) Entropy
(b) Enthalpy
(c) Internal energy
(d) Activation energy

The average rate and instantaneous rate of a reaction are equal

(a) at the start
(b) at the end
(c) in the middle
(d) when two rates have a time interval equal to zero

The rate constant of zero-order reactions has the unit

(a) s⁻¹
(b) mol L⁻¹ s⁻¹
(c) L² mol⁻² s⁻¹
(d) L mol⁻¹ s⁻¹

. A substance ‘A’ decomposes by a first-order reaction starting initially with [A] = 2.00M and after 200 min, [A] becomes 0.15M. For this reaction t₁/₂ is

(a) 53.72 min
(b) 50.49 min
(c) 48.45 min
(d) 46.45 min

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

(a) Platinized asbestos
(b) Iron with molybdenum as a promoter
(c) Copper oxide
(d) Alumina

When the rate of the reaction is equal to the rate constant, the order of the reaction is

(a) zero order
(b) first order
(c) second order
(d) third order