Bromate ions react with bromide ions in acid: BrO₃⁻ + 5Br⁻ + 6H⁺ → 3Br₂ + 3H₂O…

Bromate ions react with bromide ions in acid: $\text{BrO}_3^- + 5\text{Br}^- + 6\text{H}^+ \rightarrow 3\text{Br}_2 + 3\text{H}_2\text{O}$. The initial rates were measured at a fixed temperature. The numbers are chosen for practice.

• Run 1: $[\text{BrO}_3^-] = 0.10\ \text{mol/L}$, $[\text{Br}^-] = 0.10\ \text{mol/L}$, $[\text{H}^+] = 0.10\ \text{mol/L}$. Rate $2.1 \times 10^{-4}\ \text{mol L}^{-1}\ \text{s}^{-1}$.
• Run 2: $[\text{BrO}_3^-] = 0.20\ \text{mol/L}$, the others as in run 1. Rate $4.2 \times 10^{-4}\ \text{mol L}^{-1}\ \text{s}^{-1}$.
• Run 3: $[\text{Br}^-] = 0.30\ \text{mol/L}$, the others as in run 1. Rate $6.3 \times 10^{-4}\ \text{mol L}^{-1}\ \text{s}^{-1}$.
• Run 4: $[\text{H}^+] = 0.20\ \text{mol/L}$, the others as in run 1. Rate $8.4 \times 10^{-4}\ \text{mol L}^{-1}\ \text{s}^{-1}$.

Find the order in each reactant, the overall order and the rate constant.