Question

In the following reaction
$3B{r}_2+6C{O}_3^{2-}+3H_{2}O\to 5B{r}^{-}+Br{O}_3^{-}+6HC{O}_3^{2-}$

• A. Bromine is oxidised and carbonate is reduced
• B. Bromine is reduced and water is oxidised
• C. Bromine is neither reduced nor oxidised
• D. Bromine is both reduced and oxidised

Answer 1

The correct option is D Bromine is both reduced and oxidised

Solution: Analyzing the change in oxidation states of atoms.
Oxidation state of Br in $Br{O}_3^{-}$ :
Let oxidation state of Br be x.
𝑥 + 3 (−2 ) = −1
𝑆𝑜, 𝑥 = +5


Oxidation state: 𝐵𝑟 = 0 𝐵𝑟 = −1
𝐵𝑟 = +5
In this reaction, $B{r}_2$ is getting reduced to $B{r}^{-}$ as oxidation state of Br is decreasing from 0 to −1, and $B{r}_2$ is also getting oxidised to $Br{O}_3^{-}$ as oxidation state of 𝐵𝑟 is increasing from 0 to +5 in $Br{O}_3^{-}$ .

Thus, Bromine is both reduced and oxidised in the given reaction.

Hence option (D) is the correct answer.