During which of the following processes is phosphine $(PH_3)$ $NOT$ obtained?

Very pure $N_2$ can be obtained by

Which of the following is formed when aluminium oxide and carbon are strongly heated in dry chlorine gas?

An orange solid $(X)$ on heating gives a colourless gas $(Y)$ and only a green residue $(Z)$. Gas $(Y)$ on treatment with $Mg$ produces a white solid substance. Identify the white solid substance.

$A$ group $15$ element forms $d \pi - d \pi$ bond with transition metals. It also forms a hydride,which is the strongest base among the hydrides of other group members that form $d \pi - d \pi$ bonds. The atomic number of the element is $.......$

Which of the following oxides of nitrogen is paramagnetic?