2 NO +2 H_2 → N_2+2 H_2 O The above reaction has been studied at 800^° C. The related data are given in the table below The order of the reaction…

$$2 \mathrm{NO}+2 \mathrm{H}_2 \rightarrow \mathrm{~N}_2+2 \mathrm{H}_2 \mathrm{O} $$ The above reaction has been studied at $\displaystyle 800^{\circ} \mathrm{C}$. The related data are given in the table below

Reaction serial number	Initial Pressure of $\displaystyle \mathrm{H}_2$ / kPa	Initial Pressure of NO/kPa	Initial rate $\displaystyle \left(\frac{-\mathrm{dp}}{\mathrm{dt}}\right) /(\mathrm{kPa} / \mathrm{s})$
$\displaystyle 1$	$\displaystyle 65.6$	$\displaystyle 40.0$	$\displaystyle 0.135$
$\displaystyle 2$	$\displaystyle 65.6$	$\displaystyle 20.1$	$\displaystyle 0.033$
$\displaystyle 3$	$\displaystyle 38.6$	$\displaystyle 65.6$	$\displaystyle 0.214$
$\displaystyle 4$	$\displaystyle 19.2$	$\displaystyle 65.6$	$\displaystyle 0.106$

The order of the reaction with respect to NO is \_\_\_\_.