Hydrolysis of $PCl_5$ gives

When copper metal is treated with cold and dilute nitric acid, it forms

$A$ metalloid is

On heating with concentrated $NaOH$ solution in an inert atmosphere of $CO_{2}$,white phosphorus gives a gas. Which of the following statements is incorrect about the gas?

Which of the following oxides of nitrogen is a blue solid?

When a brown compound of manganese $(A)$ is treated with $HCl$,it gives a gas $(B)$. The gas $(B)$ taken in excess reacts with $NH_3$ to give an explosive compound $(C)$. The compounds $A$,$B$ and $C$ are: