In which of the following compounds, an element exhibits two different oxidation state?

1. ${\mathrm{NH}}_{2}\mathrm{OH}$

2. ${\mathrm{NH}}_{4}{\mathrm{NO}}_{3}$

3. ${\mathrm{N}}_{2}{\mathrm{H}}_{4}$

4. ${\mathrm{N}}_{3}\mathrm{H}$

Hint: Compound in which nitrogen present in cationic part as well as anionic part.

${\mathrm{NH}}_{4}{\mathrm{NO}}_{3}$ is actually ${\mathrm{NH}}_{4}^{+}$ and ${\mathrm{NO}}_{3}^{-}$. It is an ionic compound.

The oxidation state of nitrogen in the two species is different as shown below
Let, oxidation number of N in $\stackrel{+}{\mathrm{N}}{\mathrm{H}}_{4}$ is

$⇒\mathrm{x}+\left(4×1\right)=+1$
or

Let, oxidation number of N in ${\mathrm{NO}}_{3}^{-}$ is x