Question

Which metallic nitrate gives only one gas on heating?

Answer 1

Potassium nitrate $\left({\mathrm{KNO}}_3\right)$ or Sodium nitrate $\left({\mathrm{NaNO}}_3\right)$ are the metallic nitrate that gives only one gas on heating i.e. oxygen gas $\left({\mathrm{O}}_2\right)$.

$$\begin{gathered} 2{\mathrm{KNO}}_3\left(\mathrm{s}\right)\stackrel{∆}{\to }{\mathrm{KNO}}_2\left(\mathrm{s}\right)+{\mathrm{O}}_2\left(\mathrm{g}\right) \\ 2{\mathrm{NaNO}}_3\left(\mathrm{s}\right)\stackrel{∆}{\to }{\mathrm{NaNO}}_2\left(\mathrm{s}\right)+{\mathrm{O}}_2\left(\mathrm{g}\right) \end{gathered}$$