$2\text{NO}\text{ (g)} + \text{Cl}_2\text{ (g)} \rightleftharpoons 2\text{NOCl}\text{(s)}$
This reaction was studied at \( -10^\circ \mathrm{C} \) and the following data was obtained.
\( [\mathrm{NO}]_0 \) and \( [\mathrm{Cl_2}]_0 \) 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).
