For a first order reaction,
\(t_{1 / 2}=\frac{0.693}{k}\) ( \(k=\) rate constant )
\({\Rightarrow \quad 1} {386=\frac{0.693}{k}}\)
\({\Rightarrow \quad k} {=5 \times 10^{-4} \,\mathrm{s}^{-1}}\)
\({=0.5 \times 10^{-3}\, \mathrm{s}^{-1}}\)
$ O_3 $ $\rightleftharpoons$ $ O_2 + O$ ...... (ઝડપી) ;
$O + O_3 \rightarrow 2O_2$ ...... (ધીમી)