Which of the following on heating produces $NO_2$?

The bond energies (in $kJ \ mol^{-1}$) of $N-H$,$P-H$,and $As-H$ are respectively:

The acidic character of the group-$15$ elements' oxides in increasing order is:

Given below are two statements:
Statement $I$: The halogen that makes the longest bond with hydrogen in $HX$ has the smallest covalent radius in its group.
Statement $II$: $A$ group $15$ element's hydride $EH_3$ has the lowest boiling point among corresponding hydrides of other group $15$ elements. The maximum covalency of that element $E$ is $4$.
In the light of the above statements, choose the correct answer from the options given below.

The cyanamide process is used in the formation of:

What are the products obtained when ammonia is reacted with excess chlorine?