Question

For the gas phase decomposition $A\to 2B$, the rate constant is $6.93\times {10}^{-3}$ $mi{n}^{-1}$ at 300K. The percentage of A remaining at the end of 300 minutes is :

• A. 75
• B. 50
• C. 25
• D. 12.5

Answer 1

The correct option is D 12.5

$ln\left[\frac{Ao}{A}\right]=kt$
$=6.93\times {10}^{-3}\times 300$
$\frac{Ao}{A}=8$
$\frac{A}{Ao}=.1250$
$\frac{A}{Ao}\times 100$ =12.5%