Question

Assertion :${Br}_2$ is oxidised to $Br{O}_3^{-}$ in basic medium. Reason: When ${Br}_2$ is passed into hot $NaOH$, it disproportionates to ${Br}^{-}$ and $Br{O}_3^{-}$.

• A. Both Assertion and Reason are correct and Reason is the correct explanation for Assertion
• B. Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion
• C. Assertion is correct but Reason is incorrect
• D. Assertion is incorrect but Reason is correct

Answer 1

Answer: (D)

When $B{r}_2$ is passed into hot $NaOH$, it disproportionates to $B{r}^{-}$ and $Br{O}_3^{-}$.
The oxidation number of bromine in $B{r}_2$ is $0$.
The oxidation number of bromine in $Br{O}_3^{-}$ is $+5$.
The oxidation number of bromine in $B{r}^{-}$ is $-1$.
Thus, in basic medium, $B{r}_2$ is oxidized to $Br{O}_3^{-}$ and at the same time, it is reduced to $B{r}^{-}$.
Hence, assertion is incorrect but Reason is correct.