In an acidic medium, the rate of reaction between (${{\mathrm{BrO}}_3}^{⊝}$) and ${\mathrm{Br}}^{⊝}$ ions is given by the expression

$\frac{-d\left[{\mathrm{BrO}}_3^{\ominus }\right]}{dt}=k\left[{\mathrm{BrO}}_3^{\ominus }\right]\left[{\mathrm{Br}}^{\ominus }\right]{\left[{\mathrm{H}}^{\oplus }\right]}^2$

It means

The rate constant of overall reaction is 4 s^-1. 

The rate of reaction is independent of the concentration of acid

The change in pH of the solution will not affect the rate.

Doubling the concentration of ${\mathrm{H}}^{\oplus }$ ions will increase the reaction rate by 4 times.