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…

A 'p'-block element (E) and hydrogen form a binary cation $\displaystyle \left(\mathrm{EH}_{\mathrm{x}}\right)^{+}$, while $\displaystyle \mathrm{EH}_3$ on treatment with $\displaystyle \mathrm{K}_2 \mathrm{HgI}_4$ in alkaline medium gives a precipitate of basic mercury(II)amido-iodine. Given below are first ionisation enthalpy values $\displaystyle \left(\mathrm{kJ} \mathrm{mol}^{-1}\right)$ for first element each from group $\displaystyle 13$, $\displaystyle 14$, $\displaystyle 15$ and 16. Identify the correct first ionisation enthalpy value for element E .