The proposed mechanism for a reaction is
1. ClO-(aq) + H2O(l) => HClO(aq) + OH-(aq) SLOW
2. I-(aq) + HClO(aq) => HIO(aq) + Cl-(aq) FAST
3. OH-(aq) + HIO(aq) => H2O(l) + IO-(aq) FAST

Which of the following would be a rate law for the reaction?

1. rate = k[ClO-][H2O][I-][OH-]
2. rate = k[ClO-][H2O]
3. rate = k[OH-][HIO]
4. rate = k[I-][HClO]
5. rate = k[ClO-][H2O][I-]

Rate law is defined as the function of concentration of reactants in a chemical reaction. Rate law of a reaction depends on the slow step of a chemical reaction.

For example, [tex]ClO^{-}(aq) + H_{2}O(l) \rightarrow HClO(aq) + OH^{-}(aq)[/tex] is a slow step reaction.

Therefore, its rate law will be expressed as follows.

Rate law = [tex]k[ClO^{-}][H_{2}O][/tex]

Thus, we can conclude that out of the given options [tex]k[ClO^{-}][H_{2}O][/tex] would be a rate law for the given reaction.