Q24 / 200 · Manipal (MET) 2014 · Chemistry
Consider the following reaction in aqueous solution.
$\begin{aligned}
& 5 \mathrm{Br}^{-}(a q)+\mathrm{BrO}_3^{-}(a q)+6 \mathrm{H}^{+}(a q) \longrightarrow 3 \mathrm{Br}_2(a q) \\
&+3 \mathrm{H}_2 \mathrm{O}(l)
\end{aligned}$
If the rate of appearance of $\mathrm{Br}_2$ at a particular moment during the reaction is $0.025 \mathrm{Ms}^{-1}$, what is the rate of disappearance (in $\mathrm{Ms}^{-1}$ ) of $\mathrm{Br}^{-}$at that moment?
If the rate of appearance of $\mathrm{Br}_2$ at a particular moment during the reaction is $0.025 \mathrm{Ms}^{-1}$, what is the rate of disappearance (in $\mathrm{Ms}^{-1}$ ) of $\mathrm{Br}^{-}$at that moment?
- A$0.025 \mathrm{~ms}^{-1}$
- Correct answerB$0.042 \mathrm{~ms}^{-1}$
- C$0.075 \mathrm{~ms}^{-1}$
- D$0.125 \mathrm{~ms}^{-1}$
Solution
The two rates are related as- $\left.\frac{1}{5} \frac{d\left[\mathrm{Br}^{-}\right]}{d t}=\frac{1}{3} \frac{d\left[\mathrm{Br}_2\right]}{d t}\right]$ $-\frac{d\left[\mathrm{Br}^{-}\right]}{d t}=\frac{5}{3} \frac{d\left[\mathrm{Br}_2\right]}{d t}=\frac{5}{3} \times 0.025=0.042 \mathrm{ms}^{-1}$
Hence, the correct answer is option: 'B'.