Rate $=\mathrm{k}\left[\mathrm{PH}_{3}\right]$
It is dependent on surface coverage because at low pressure, surface area covered is proportional to partial pressure
of $\mathrm{PH}_{3}$ and it is first order w.t.t. $\mathrm{PH}_{3}$
$\theta=\frac{k P}{1+k P}$
$\theta=$ fraction of surface area covered at low pressure $\theta=\mathrm{k} \mathrm{P}$
$S{{O}_{2}}C{{l}_{2}}\to S{{O}_{2}}+C{{l}_{2}}$ નો વેગ અચળાંક $2.2 \times 10^{-5}\, s^{-1}$ છે. આ વાયુને $90\, min$ સુધી ગરમ કરતા કેટલા $(\%)$ ટકા $SO_2Cl_2$ નુ વિધટન થશે ?