Question

Order the following molecules from lowest to highest oxidation state of the nitrogen atom:

${\mathbf{HNO}}_{\mathbf{3}}$,${\mathbf{NH}}_{\mathbf{4}}\mathbf{Cl}$,${\mathbf{N}}_{\mathbf{2}}\mathbf{O}$,${\mathbf{NO}}_{\mathbf{2}}$,${\mathbf{NaNO}}_{\mathbf{2}}$.

Short answer

Highest oxidation state of the nitrogen atom is${\mathrm{HNO}}_3$

Step-by-step solution

Oxidation state of HNO3

The sum of the oxidation number is proportional to the charge on molecules. The oxidation number for oxygen is $-2$, the oxidation number of hydrogen is $+1$

$1+x+3\times (-2)=0$

$x=+5$

Oxidation state of NO2

The oxidation state of nitrogen atom in ${\mathrm{NO}}_2$is

$\mathrm{x}+2\times (-2)=0$

$x=+4$

The oxidation state of N2O and NaNO2

The oxidation state of nitrogen atom in ${\mathrm{N}}_2\mathrm{O}$is;

$2\mathrm{x}+1\times (-2)=0$

$x=1$

The oxidation state of NaNO2 is;

$\begin{array}{l}1+\mathrm{x}+2\times (-2)=0\\ \mathrm{x}=+3\end{array}$

The oxidation state of nitrogen atom in${\mathrm{NaNO}}_2$is$+3$

The oxidation state of NH4Cl is;

$\begin{array}{l}x+4-1=0\\ x=-3\end{array}$

The oxidation state of nitrogen atom in${\mathrm{NH}}_4\mathrm{Cl}$is$-3$

Conclusion

The lowest to highest oxidation state of the nitrogen atom is NH₄Cl ,${\mathrm{N}}_2\mathrm{O}$ , ${\mathrm{NaNO}}_2$, ${\mathrm{NO}}_2$ and ${\mathrm{HNO}}_3$.