Name a nitrate of metal which on heating does not give ${\mathrm{NO}}_2$.

1. Definition: Decomposition reaction is defined as a reaction where one reactant molecule splits down into two or more further products.
2. Metal nitrate on heating generally gives their oxides, Nitrogen dioxide and Oxygen.
3. But their is an exception as Sodium nitrate (${\mathbf{NaNO}}_{\mathbf{3}}$) and Potassium nitrate (${\mathbf{KNO}}_{\mathbf{3}}$) does not form their oxides, Nitrogen dioxide and Oxygen.
4. Sodium nitrate (${\mathbf{NaNO}}_{\mathbf{3}}$) on heating gives Sodium nitrite (${\mathbf{NaNO}}_{\mathbf{2}}$) and Oxygen (${\mathbf{O}}_{\mathbf{2}}$).
5. The decomposition reaction of Sodium nitrate is shown below.
   $$\begin{gathered} 2{\mathrm{NaNO}}_3\left(\mathrm{s}\right)\stackrel{∆}{\to }2{\mathrm{NaNO}}_2\left(\mathrm{s}\right)+{\mathrm{O}}_2\left(\mathrm{g}\right) \\ \mathrm{Sodium}\mathrm{Sodium}\mathrm{Oxygen} \\ \mathrm{nitrate}\mathrm{nitrite} \end{gathered}$$
6. Therefore, a nitrate of metal which on heating does not give ${\mathrm{NO}}_2$ is Sodium nitrate (${\mathbf{NaNO}}_{\mathbf{3}}$).