Ammonia reacts with an excess of chlorine to form:

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:

Nitric acid is an oxidising agent and reacts with $PbO$ but it does not react with $PbO_{2}$. Explain why?

Which element forms unstable trihalides?

The pair in which phosphorus atoms have a formal oxidation state of $+3$ is:

$BiCl_3$ on hydrolysis forms a white precipitate of