JEE Advanced 2018 · Paper 1 · Chemistry Q3

ChemistryMultiple correct+4 / -2Question 21 of 54

Based on the compounds of group 15 elements, the correct statement(s) is (are)

\ce{Bi2O5}

is more basic than

\ce{N2O5}

\ce{NF3}

is more covalent than

\ce{BiF3}

\ce{PH3}

boils at lower temperature than

\ce{NH3}

The N−N single bond is stronger than the P−P single bond

Answer and worked solution

Official answer: A, B, C

(A) Metallic character, and with it the basicity of the oxides, increases down group 15. $\ce{N2O5}$ is strongly acidic. $\ce{Bi2O5}$ is more basic. True.
(B) By Fajans' rules, the small, highly polarising N(III) makes $\ce{NF3}$ covalent. $\ce{BiF3}$ is largely ionic. True.
(C) $\ce{NH3}$ is hydrogen bonded and $\ce{PH3}$ is not, so $\ce{PH3}$ boils lower. True.
(D) The short N-N bond suffers strong lone-pair-lone-pair repulsion, so it is weaker than P-P. False.

(A), (B), (C)

Topics:Group 15 Hydrogen bonding Ionic bonding

JEE Advanced 2018 · Paper 1, Chemistry question 3