By the action of hot conc. $H_2SO_4,$ phosphorus changes to

When concentrated nitric acid is heated,it decomposes to give

The structural formula of hypophosphorus acid is

The reaction of $HNO_3$ with $P_4O_{10}$ produces ....

$A$ $p$-block element $(E)$ and hydrogen form a binary cation $(EH_{x}^{+})$, while $EH_{3}$ on treatment with $K_{2}HgI_{4}$ in alkaline medium gives a precipitate of basic mercury$(II)$amido-iodine. Given below are first ionisation enthalpy values $(kJ \ mol^{-1})$ for the first element of each group $13, 14, 15$, and $16$. Identify the correct first ionisation enthalpy value for element $E$.

Which element does not show the inert pair effect?