Question

The half-life period for a reaction at an initial concentration of $0.5$ and $1.0M$ are $200sec$ and $100sec$ respectively. The order of the reaction is:

• A. 0
• B. 1
• C. 2
• D. 3

Answer 1

The correct option is C 2

$t_{\frac{1}{2}}\alpha \frac{1}{a^{n-1}}$

where $n$ is the order of the reaction.

$\frac{200}{100}={\left(\begin{array}{c}\frac{1}{0.5}\end{array}\right)}^{n-1}$

$2=2^{n-1}$

$n-1=1$

$n=2$

Hence, the order of the reaction is 2.