Question

The half-life of a reaction is inversely proportional to the square of the initial concentration of the reactant. Then the order of the reaction is

• A. 0
• B. 1
• C. 2
• D. 3
• E. 0.5

Answer 1

Answer: (D)

For nth order reaction,
$t_{1/2} \propto\frac{1}{a^{n-1}}$
Given, $t_{1/2} \propto \frac{1}{a^2}$
On comparing,
$a^{n-1} = a^2$
$n-1 = 2$
$\therefore n = 3$
Hence, the order of reaction is 3.