The chemical reaction 2O3+ 3O2 proceeds as follows:O3⇌O2+O            (fast)O+O3→2O2          (slow)The rate law expression should be

2O3⟶kI3O2Mechanism:O3⇌keqO2+O       (fast)O+O3⟶k2O2    (slow)Rate of the reaction from the slow step isr=k[O]O3Fast step is in equilibrium, the concentration of [O] is calculated from this stepkeq=O2[O]O3 ∴[O]=ku⋅O3O2Substitute the value of [O] in Eq. (i)r=k⋅keq⋅O3O3O2=k1O32O2=k1O32O2−1