Why does $PCl_3$ fume in moisture?

Consider two reactions:
$(I) \, Zn + \text{conc. } HNO_3 \text{ (hot)} \to Zn(NO_3)_2 + X + H_2O$
$(II) \, Zn + \text{dil. } HNO_3 \text{ (cold)} \to Zn(NO_3)_2 + Y + H_2O$
Compound $X$ and $Y$ are respectively:

What is the range of oxidation states exhibited by phosphorus?

The compound$(s)$ which generate$(s)$ $N_2$ gas upon thermal decomposition below $300^{\circ} C$ is (are)
$(A)$ $NH_4 NO_3$
$(B)$ $(NH_4)_2 Cr_2 O_7$
$(C)$ $Ba(N_3)_2$
$(D)$ $Mg_3 N_2$

Select the incorrect statement regarding trihalides $(EX_3)$ and pentahalides $(EX_5)$ of the nitrogen family.

Which reaction does not produce ammonia?