Question

Which among the following is a false statement ?

• A. Rate of zero order reaction is independent of initial concentration of reactant.
• B. Half-life of a zero order reaction is inversely proportional to the rate constant.
• C. Molecularity of a reaction may be zero.
• D. For a first order reaction, $t_{1/2} = 0.693/k$.

Hint:

For reaction orders, remember that molecularity and order are often confused. Molecularity refers to the number of molecules involved in the reaction, while order refers to the powers of concentrations in the rate law.

Answer 1

The Correct Option is C

Option (1) is true because, for zero order reactions, the rate is independent of the concentration of reactants.
Option (2) is also correct as the half-life for a zero order reaction is given by $t_{1/2} = [A]_0 / 2k$, which is inversely proportional to the rate constant.
Option (3) is false because molecularity refers to the number of reacting molecules and cannot be zero for a valid reaction.
Option (4) is true as for a first order reaction, the half-life is given by $t_{1/2} = 0.693/k$.
Hence, the false statement is (3).