Question

Name a nitrate of metal which on heating does not give nitrogen dioxide

Answer 1

Nitrates of monovalent alkali metals on heating do not give NO2 on heating. Metals like sodium and potassium.
For example;
2NaNO3 -----heat------- 2NaNO2 + O2

Answer 2

Name of a nitrate of a metal that on heating doesn’t give nitrogen dioxide $\left(\mathrm{NO}_{2}\right)$ is Sodium Nitrate $\bold{\left(\mathrm{NaNO}_{3}\right)}$. As a matter of fact nitrates of all the monovalent alkaline metals like Sodium and Potassium do not release nitrogen dioxide on being heated. Instead, they form a lower $\mathrm{NO}_{\mathrm{x}}$ and release oxygen gas.  

The equation of this reaction is as follows:

$\bold{2 \mathrm{NaNO}_{3}+\text { heat } \rightarrow 2 \mathrm{NaNO}_{2}+\mathrm{O}_{2}}$

In this reaction, there is no release of nitrogen gas only oxygen gets released.