$H_3PO_2$ $\xrightarrow{140^{\circ}C}$ $A$ $\xrightarrow{250^{\circ}C}$ $B$ $\xrightarrow{316^{\circ}C}$ $C$
Compound $(C)$ is

In the modern process,phosphorus is manufactured by:

White phosphorus on reaction with concentrated $NaOH$ solution in an inert atmosphere of $CO_{2}$ gives phosphine and compound $(X)$. $(X)$ on acidification with $HCl$ gives compound $(Y)$. The basicity of compound $(Y)$ is

Find the correct statements related to group $15$ hydrides.
$A$. Reducing nature increases from $NH_3$ to $BiH_3$
$B$. Tendency to donate lone pair of electrons decreases from $NH_3$ to $BiH_3$
$C$. The stability of hydrides decreases from $NH_3$ to $BiH_3$
$D$. $HEH$ bond angle decreases from $NH_3$ to $SbH_3$ ($E$ = Elements of group $15$)
Choose the correct answer from the options given below:

At what temperature is white phosphorus heated to obtain red phosphorus (in $K$)?

$NO_2$ is a mixed oxide. This is proved by the fact that it reacts with $H_2O$ and then with $NaOH$ to form: