Question

The decomposition of ozone proceeds as
$O_3\leftrightarrow O_2+O$ (fast)
$O+O_3\to 2O_2$ (slow)
the rate expression should be:

• A. $Rate=K[O_3{]}^2$
• B. $Rate=K\left[O_3{]}^2\right[O_2{]}^{-1}$
• C. $Rate=K\left[O_3\right]\left[O_2\right]$
• D. $Rate=K\left[O_3\right][O_2{]}^{-1}$

Answer 1

The correct option is B $Rate=K\left[O_3{]}^2\right[O_2{]}^{-1}$

slow step is rate determining step.

Hence rate of reaction is given as:
$rate=k_2\left[O\right]\left[O_3\right]$
by chemical $e{q}^n$
$k_1=\frac{\left[O_2\right]\left[0\right]}{O_3}$
$\left[O\right]=\frac{k_1\left[O_3\right]}{\left[O_2\right]}$
so
rate= $k_1{k}_2\left[O_3{]}^2\right[O_2{]}^{-1}$
$r=k\left[O_3{]}^2\right[O_2{]}^{-1}$