Question

What do you understand by order of a reaction? Calculate the total order of those reactions which have velocity equations:
(i) Velocity \( = K[A]^{1/2}[B]^{3/2} \)
(ii) Velocity \( = K[A]^3[B]^{-1} \)

Hint:

The order of a reaction is the sum of the exponents of the concentration terms in the rate law equation. It determines how the rate of reaction changes with the concentration of reactants.

Answer 1

The order of a reaction refers to the sum of the exponents of the concentrations of the reactants in the rate law. The order indicates how the rate of reaction is affected by the concentration of the reactants.
1. For the first velocity equation \( \text{Velocity} = K[A]^{1/2}[B]^{3/2} \):
The total order of the reaction is the sum of the exponents of the concentrations of the reactants. In this case, the exponents are 1/2 for A and 3/2 for B. Therefore, the total order is:
\[ \text{Total order} = \frac{1}{2} + \frac{3}{2} = 2 \] 2. For the second velocity equation \( \text{Velocity} = K[A]^3[B]^{-1} \):
Similarly, the total order of the reaction is the sum of the exponents of the concentrations of the reactants. Here, the exponents are 3 for A and -1 for B. Therefore, the total order is:
\[ \text{Total order} = 3 + (-1) = 2 \] Thus, for both reactions, the total order is 2.