Question

What is the oxidation number of $\mathrm{N}$ in ammonia?

Answer 1

Oxidation number: Oxidation number denotes the oxidation state of an element in a compound ascertained according to a set of rules formulated on the basis that electron pair in a covalent bond belongs entirely to a more electronegative element.

Calculating the oxidation number of Nitrogen(N) in ammonia $\left({\mathrm{NH}}_3\right)$:

The oxidation state of Hydrogen(H) = +1

Consider the oxidation state of nitrogen(N) = x

Now,

$$\begin{gathered} x+\left(1\times 3\right)=0 \\ x=-3 \end{gathered}$$

Hence, the oxidation number of $\mathrm{N}$ in ammonia is $-3$.