Which of the following is a colorless solid?

$A$ metal $(X)$ dissolves in both dilute $HCl$ and dilute $NaOH$ to liberate $H_2$ gas. Addition of $NH_4Cl$ and excess $NH_4OH$ to an $HCl$ solution of $(X)$ produces $(Y)$ as a precipitate. $(Y)$ is also produced by adding $NH_4Cl$ to the $NaOH$ solution of $(X)$. The species $(X)$ and $(Y)$,respectively,are:

How can you synthesise nitric oxide in the laboratory?

Nitrogen is a relatively inactive element because

What is produced when $Ag$ is heated with concentrated $HNO_3$?

What is formed when ammonia reacts with excess chlorine gas?