If the rate for the chemical reaction is expressed as Rate $=\mathrm{K}\left[\mathrm{A}\right][\mathrm{B}{]}^{\mathrm{n}}$, then order of the reaction is
 

$\text{ If rate }=\mathrm{k}\left[\mathrm{A}{]}^{\mathrm{m}}\right[\mathrm{B}{]}^{\mathrm{n}}\text{, then order of reaction }=\mathrm{m}+\mathrm{n}$

The given rate is $=\mathrm{K}\left[\mathrm{A}\right][\mathrm{B}{]}^{\mathrm{n}}$

Here the order will be 1 + n