Question
Chemistry Question on Chemical Kinetics
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
Answer
3
Explanation
Solution
For nth order reaction,
\hspace25mm t_{1/2} ? \frac{1}{a^{n-1}}
Given, \hspace20mm t_{1/2} ? \frac{1}{a^2}
On comparing,
\hspace25mm a^{n-1} = a^2
\hspace25mm n-1 = 2
\therefore \hspace25mm n = 3
Hence, the order of reaction is 3.