Q$2.(6$ Marks$)$

The decomposition of $N_2{O}_5$ is postulated to occur by the following mechanism:

$N_2{O}_5\{\begin{array}{c}\text{:}{k}_3\end{array}{?}_{k_2}N{O}_2+N{O}_3^{**}$

$N{O}_3^{+}{k}_{3}N{O}^{+}+O_2$

$NO+N{O}_3^{+},k_{4}2N{O}_2$

Using the steady state approximation, show that the expression for the rate of disappearance of $N_2{O}_{,is}$

$-r_{N_2{O}_4}=\frac{2k_1{k}_3{C}_{N_2{O}_3}}{2k_3+k_2{C}_{N{O}_2}}$