2NO ( g ) + Cl _ 2 ( g ) ⇌ 2NOCl ( s ) This reaction was studied at...

$2NO ( g ) + {Cl}_{2} ( g ) ⇌ 2NOCl ( s )$
This reaction was studied at $- 10 ° C$ and the following data was obtained

$\begin{cases}run & [ NO{]}_{0} & {\left[{Cl}_{2}\right]}_{0} & {r}_{0} \\ 1 & 0.10 & 0.10 & 0.18 \\ 2 & 0.10 & 0.20 & 0.35 \\ 3 & 0.20 & 0.20 & 1.40\end{cases}$

$[ NO{]}_{0}$ and ${\left[{Cl}_{2}\right]}_{0}$ are the initial concentrations and ${r}_{0}$ is the initial reaction rate. The overall order of the reaction is
(Round off to the Nearest Integer).