Question

The kinetics of the reaction below were studied and it was determined that the reaction rate increased by a factor of 9 when the concentration of B was tripled. The reaction is order in B:_________.
A) zero
B) first
C) second
D) third
E) one-half

Answer 1

Answer:

C) second

Explanation:

According to the law of mass action:-

The rate of the reaction is directly proportional to the active concentration of the reactant which each are raised to the experimentally determined coefficients which are known as orders. The rate is determined by the slowest step in the reaction mechanics.

Order of in the mass action law is the coefficient which is raised to the active concentration of the reactants. It is experimentally determined and can be zero, positive negative or fractional.

The order of the whole reaction is the sum of the order of each reactant which is raised to its power in the rate law.

The reaction rate increased by 9 times when the concentration of B is tripled it means that:-

R = [B]²

[B'] = 3[B]

R' = (3[B])² = 9[B]² = 9 R

The order is 2.