Question

5 If concentration time graph of a reactant indicates a constant half-life, then the order
reaction with respect to that reactant is:
(2018)
A) zero order
C) second order
B) half order
D) first order
​

Answer 1

Explanation:

A .Zeroth-Order Reactions. rate=k. Because rate is independent of reactant concentration, a graph of the concentration of any reactant as a function of time is a straight line with a slope of −k. The value of k is negative because the concentration of the reactant decreases with time.

Answer 2

As specified in question that graph indicates a constant half life with respect to concentration that’s possible only for 1st order reaction.

For 1st order reaction
Half life = ln 2/ K = 0.693 / K

This expression show its independent of concentration.