The number of $P-O-P$ bonds in $H_4P_2O_7$,$(HPO_3)_3$ and $P_4O_{10}$ are respectively.

The reaction of $P_4$ with $X$ leads selectively to $P_4O_6$. The $X$ is

$H_3PO_3$ is

The number of oxygen atoms bonded to one phosphorus atom in $P_4O_6$ is

Which halide of nitrogen is least basic?

In the following reaction,identify the nature of the product formed by the complete hydrolysis of the underlined atom at $R.T.$:
$\underline{N}F_3 + H_2O \longrightarrow \text{No reaction}$