The correct expression for the rate of reaction given below is:
5Br(aq)+BrO3(aq)+6H+(aq)3Br2(aq)+3H2O(l)

1. Δ[Br]Δt=5Δ[H+]Δt 2. Δ[Br]Δt=65Δ[H+]Δt
3. Δ[Br]Δt=56Δ[H+]Δt 4. Δ[Br]Δt=6Δ[H+]Δt
HINT: Rate of reaction =1stoichiometric coefficient ofreactant×d[concentration of reactant]dT
Explanation:
The chemical reaction is as follows:

5Br(aq)+BrO3(aq)+6H+(aq)3Br2(aq)+3H2O(l)

Rate law expression for the above equation can be written as

15Δ[Br]Δt=Δ[BrO3]Δt=16Δ[H+]Δt=+13Δ[Br2]ΔtΔ[Br]Δt=Δ[BrO3]Δt=56Δ[H+]ΔtΔ[Br]Δt=56Δ[H+]Δt