Question

Indicate in each reaction which one is oxidised or reduced if any:

$3N_2{H}_4+2{BrO}_3^{-}\to 3N_2+2B{r}^{-}+6H_{2}O$
In the above reaction, which one of the following is oxidised?

• A. $N_2{H}_4$
• B. ${BrO}_3^{-}$
• C. $H_{2}O$
• D. None of these

Answer 1

Answer: (A)

$N_2{H}_4$

The oxidation number of N increases from -2 to 0. Thus, $N_2{H}_4$ is oxidized.
The oxidation number of Br decreases from +5 to -1. Thus, ${Br{O}_3}^{-}$ is reduced.