Which of the following is the correct order of stability of hydrides of Group $15$ elements?

The nitrogen-containing compound produced in the reaction of $HNO_3$ with $P_4O_{10}$:
$(A)$ can also be prepared by the reaction of $P_4$ and $HNO_3$
$(B)$ is diamagnetic
$(C)$ contains one $N-N$ bond
$(D)$ reacts with $Na$ metal producing a brown gas

The number of hydroxyl groups in pyrophosphoric acid is ......... .

What are the products formed when ammonia reacts with excess chlorine?

The product formed in the reaction of $SOCl_2$ with white phosphorus is:

What is the product of the reaction between $HNO_3$ and $P_4O_{10}$?