Question
In the reaction :
$$3B{r_2} + 6CO_3^{2 - } + 3{H_2}O \to $$ $$5B{r^ - } + BrO_3^ - + 6HCO_3^ - $$
A.
Bromine is reduced and carbonate ion is oxidised.
B.
Bromine undergoes disproportionation.
C.
Bromine is reduced and water is oxidised.
D.
Only water is oxidised to carbonic acid.
Answer :
Bromine undergoes disproportionation.
Solution :
$$3B{r_2} + 6CO_3^{2 - } + 3{H_2}O \to $$ $$5B{r^ - } + BrO_3^ - + 6HCO_3^ - $$
Here $$B{r_2}$$ is both reduced and oxidised.
$$\eqalign{
& B{r_2}\left( 0 \right) \to B{r^ - }\left( { - 1} \right)\left( {{\text{reduction}}} \right) \cr
& B{r_2}\left( 0 \right) \to BrO_3^ - \left( { + 5} \right)\left( {{\text{oxidation}}} \right) \cr} $$