Chapter 12, Problem 6E

Consider the following reaction in aqueous solution:

$5{\text{Br}}^{-}\left(aq\right)+{\text{BrO}}_3{}^{-}\left(aq\right)+6{\text{H}}^{+}\left(aq\right)\to 3{\text{Br}}_2\left(aq\right)+3{\text{H}}_{\text{2}}O\left(l\right)$

If the rate of disappearance of ${\text{Br}}^{-}\left(aq\right)$ at a particular moment during the reaction is $3.5\times {10}^{-4}M{s}^{-1}$, what is the rate of appearance of

$3{\text{Br}}_2\left(aq\right)$ at that moment?