Question

For an elementary reaction $2A+B\to A_{2}B$,
if the volume of the vessel is quickly reduced to half of its original volume, then the rate of the reaction will:

• A. Be unchanged
• B. Increase by four times
• C. Increase by eight times
• D. Decrease by eight times

Answer 1

The correct option is C Increase by eight times

The rate of the reaction is
$r=k\left[A{]}^2\right[B]$
When the volume will be reduced to half, then rate of the reaction will be
$r_1=k\left[2A{]}^2\right[2B]=8k[A{]}^2\left[B\right]=8r$
So the rate increases by $8$ times