Q. In a reaction, A + B → Product, rate is doubled when the concentration of B is doubled, and rate increases by a factor of 8 when the concentrations of both the reactants (A and B) are doubled. Rate law for the reaction can be written as
A) Rate = k[A]²[B]
B) Rate = k[A][B]²
C) Rate = k[A]²[B]²
D) Rate = k[A][B]
Explanation
[Solution from source] Let rate = k[A]^x[B]^y. Doubling [B] doubles the rate, so y = 1. Doubling both gives 2^(x+1) = 8, so x = 2. Rate = k[A]²[B]. k[A][B]² would also give 8 for doubling both, but it would quadruple, not double, the rate on doubling [B]. Answer (1).
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.