Question

The number of electrons required to balance the following equation is:

$N{O}_3^{-}+4H^{+}+e^{-}\to 2H_{2}O+NO$

• A. $5$
• B. $4$
• C. $3$
• D. $2$

Answer 1

The correct option is C $3$

The unbalanced redox equation is as follows:

$N{O}_3^{-}+4H^{+}+e^{-}\to 2H_{2}O+NO$

The oxidation numbers for nitrogen has been assigned.

$\underset{+5}{N}{O}_3^{-}+4H^{+}+e^{\to }2H_{2}O+\underset{+2}{N}O$

This is a reduction half equation. All atoms are balanced.

We balance charges by adding the appropriate number of electrons.

$N{O}_3^{-}+4H^{+}+3e^{-}\to 2H_{2}O+NO$

This is a balanced reduction half-reaction.

Thus, the number of electrons required to balance the equation is $3$.

Hence, the correct option is $C$