Target Exam

CUET

Subject

Chemistry

Chapter

Physical: Chemical Kinetics

Question:

When we consider a balanced chemical equation of an elementary reaction which statement is applicable on it?

(A) Molecularity can never be zero
(B) Order is less than molecularity
(C) Order is equal to molecularity
(D) Order is greater than the molecularity

Choose the correct answer from the options given below:

Options:

(A), (B) and (D) only

(A), (B) and (C) only

(A) and (C) only

(B), (C) and (D) only

Correct Answer:

(A) and (C) only

Explanation:

The correct answer is Option (3) → (A) and (C) only

Complete statement:
For an elementary reaction, molecularity can never be zero and order is equal to molecularity.

Reasoning:

(A) Molecularity can never be zero – True.
Molecularity is the number of reacting species colliding in an elementary step. It is always at least 1; it cannot be zero.

(B) Order is less than molecularity – False.
This may happen in complex reactions, but not necessarily true for elementary reactions.

(C) Order is equal to molecularity – True.
For an elementary reaction, the rate law follows the stoichiometric coefficients directly, so order = molecularity.

(D) Order is greater than molecularity – False.
This is not possible for an elementary reaction.

Hence, the correct option is (A) and (C) only.