In the decomposition of lead (II) nitrate to give lead (II) oxide,nitrogen dioxide and oxygen gas,the coefficient of nitrogen dioxide (in the balanced equation) is

Sodium nitrate on heating gives nitrogen dioxide and oxygen.

On heating blue coloured powder of copper (II) nitrate in a boiling tube, copper oxide (black), oxygen gas and a brown gas X is formed. Write a balanced chemical equation of the reaction.

Which of the following gives nitrogen dioxide gas on heating ?