2NO(g) + Cl₂(g) $\rightleftharpoons$ 2NOCl(s)

This reaction was studied at $-$10$^\circ$ and the following data was obtained

Run	${[NO]_0}$	${[C{l_2}]_0}$	${r_0}$
1	0.10	0.10	0.18
2	0.10	0.20	0.35
3	0.20	0.20	1.40

${[NO]_0}$ and ${[C{l_2}]_0}$ are the initial concentrations and r₀ is the initial reaction rate.

The overall order of the reaction is __________. (Round off to the Nearest Integer).

We know, <br><br>$Rate = K{\left[ A \right]^x}{\left[ B \right]^y}$<br><br>Here from,<br><br>Exp 1 : $0.18 = K{\left[ {0.1} \right]^x}{\left[ {0.1} \right]^y}$ ..... (1)<br><br>Exp. 2 : $0.35 = K{\left[ {0.1} \right]^x}{\left[ {0.2} \right]^y}$ .... (2)<br><br>Exp. 3 : $1.40 = K{\left[ {0.2} \right]^x}{\left[ {0.2} \right]^y}$ .... (3)<br><br>(2) $\div$ (3)<br><br>$${{0.35} \over {1.40}} = {{K \times {{\left[ {0.1} \right]}^x}{{\left[ {0.2} \right]}^y}} \over {K \times {{\left[ {0.2} \right]}^x}{{\left[ {0.2} \right]}^y}}}$$<br><br>$\Rightarrow {1 \over 4} = {\left( {{1 \over 2}} \right)^x}$<br><br>$\Rightarrow x = 2$<br><br>(1) $\div$ (2)<br><br>$\left( {{1 \over 2}} \right) = {\left( {{1 \over 2}} \right)^y}$<br><br>$\Rightarrow y = 1$ <br><br>$\therefore$ x + y = 3