Chemistry - Chemical Kinetics Question with Solution | TestHub

Consider the reaction : $${\mathrm{Cl}}_2(\mathrm{aq})+{\mathrm{H}}_2\mathrm{S}(\mathrm{aq})\to \mathrm{S}(\mathrm{s})+2{\mathrm{H}}^{+}(\mathrm{aq})+2{\mathrm{Cl}}^{-}(\mathrm{aq})$$ The rate equation for this reaction is rate $=\mathrm{k}\left[{\mathrm{Cl}}_2\right]\left[{\mathrm{H}}_2\mathrm{S}\right]$ Which of these mechanisms is/are consistent with this rate equation? (A) ${\mathrm{Cl}}_2+{\mathrm{H}}_{2}S\to {\mathrm{H}}^{+}+{\mathrm{Cl}}^{-}+{\mathrm{Cl}}^{+}+{\mathrm{HS}}^{-}$ (slow) ${\mathrm{Cl}}^{+}+{\mathrm{HS}}^{-}\to {\mathrm{H}}^{+}+{\mathrm{Cl}}^{-}+\mathrm{S}\text{ (fast) }$

(B) ${\mathrm{H}}_2\mathrm{S}\iff {\mathrm{H}}^{+}+{\mathrm{HS}}^{-}$ (fast equilibrium)

${\mathrm{Cl}}_2+{\mathrm{HS}}^{-}\to 2{\mathrm{Cl}}^{-}+{\mathrm{H}}^{+}+\mathrm{S}$ (slow)