Consider the reaction between chlorine and nitric oxide ${\mathrm{Cl}}_2\left(\mathrm{g}\right)+2\mathrm{NO}\left(\mathrm{g}\right)\to 2\mathrm{NOCl}\left(\mathrm{g}\right)$ 
On doubling the concentration of both reactants, the  rate of the reaction increases by a factor of   8  however, if only the concentration of $C{l}_2$ is doubled, the rate increases by a factor of 2. The order of this reaction with respect to NO is :