Question

When $Br{O}_3^{-}$ ion reacts with $B{r}^{-}$ ion in acid solution and $B{r}_2$ is liberated. The equivalent weight of $KBr{O}_3$ in this reaction is:

• A. M/8
• B. M/3
• C. M/5
• D. M/6

Answer 1

The correct option is C M/5

Explanation: For the given disproportionation or redox reaction in acidic medium, reaction follows:

$Br{O}_3^{-}+5B{r}^{-}+6H^{+}\to 3B{r}_2+3H_{2}O$

Equivalent weight in this reaction is defined as the molar mass divided by the $n-$ factor.

$n-$ factor is the number of electrons lost and gained in disproportionation reaction. The number of these two should be same.

For the above reaction, $n$ factor = $5$

$Equivalentweight=\frac{Molecularweight}{n}$

As $1mole$ of $Br{O}_3^{-}$ of are used in the reaction

Mass of $Br{O}_3^{-}$ = 1M

Therefore,$Equivalentweight=\frac{M}{5}$

Option C is correct