Question

What is the change in the rate of a second order reaction when the concentration of the reactant is increased by 2 times its initial value?

(a) It doubles

(b) No change

(c) It quadruples

(d) It triples

This question was posed to me in final exam.

Question is from Chemical Kinetics topic in portion Chemical Kinetics of Chemistry – Class 12

Answer 1

The correct option is (c) It quadruples

To explain I would say: Let the initial concentration of reactant = [A]

           Given concentration of reactant = 2 x [A]

           We know that the rate of a second order reaction = k x [A]^2

            Therefore, rate for 2 x [A] = k x 4 x [A]^2

Therefore, the rate quadruples when the concentration of the reactant is doubled in a second order kinetic reaction.