p Block Elements Part 3

Concept:The bond length in hydrogen halides ($\mathrm{HX}$) increases down the halogen group as the atomic size increases. Boiling points of group 15 hydrides ($\mathrm{EH_3}$) are influenced by hydrogen bonding and molecular size.Explanation:The bond length order in $\mathrm{HX}$ is: $\mathrm{HI} > \mathrm{HBr} > \mathrm{HCl} > \mathrm{HF}$.The longest bond is in $\mathrm{HI}$, where iodine (I) has the largest covalent radius, not the smallest.Thus, Statement I is false because the halogen making the longest bond has the largest covalent radius.The boiling point order of group 15 hydrides is: $\mathrm{PH_3} < \mathrm{AsH_3} < \mathrm{NH_3} < \mathrm{SbH_3} < \mathrm{BiH_3}$.The lowest boiling point is shown by $\mathrm{PH_3}$, so element E is phosphorus (P).Phosphorus can exhibit a covalency greater than 4, for example up to 5 in $\mathrm{PCl_5}$ and up to 6 in $\mathrm{PF_6^-}$.Therefore, the statement that the maximum covalency of E is 4 is false.Thus, Statement II is also false.Answer:Both Statement I and Statement II are false.Correct option: D.