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 rate of reaction will change by 'x' times. Find 'x'.

Answer 1

We know,
$\text{rate}\propto {\text{[reactant]}}^n\Rightarrow rate=K[reactant{]}^n$
For an elementary reaction,
$rate\left(r_1\right)=K\left[A{]}^2\right[B]$
Again, $\text{concentration}=\frac{\text{mole}}{\text{volume}}$
If we reduced the volume by half, then concentration will be twice.
So, $rate\left(r_2\right)=K\left[2A{]}^2\right[2B]$
$r_2=8K\left[A{]}^2\right[B]as{r}_1=K[A{]}^2\left[B\right]\therefore r_2=8r_1$
$\text{Hence rate of reaction will become 8 times of}{r}_1$.