Nitrogen is obtained when $NaNO_2$ reacts with

The number of $P-O-P$ bridges in the structure of phosphorus pentoxide $(P_4O_{10})$ and phosphorus trioxide $(P_4O_6)$ are respectively:

Which of the following matches is correct?

On reaction with $Cl_2$,phosphorus forms two types of halides $A$ and $B$. Halide $A$ is a yellowish-white powder,while halide $B$ is a colourless oily liquid. Identify $A$ and $B$ and write the formulas of their hydrolysis products.

In the $15^{th}$ group of the periodic table,the elements $N, P, As, Sb$,and $Bi$ are present. As we move from $N$ to $Bi$,how do the oxides with the general formula change?

What is the maximum concentration of aqueous $HNO_3$ that can be obtained by distillation with concentrated $H_2SO_4$ in terms of percentage by mass (in $\%$)?