Question

Among the following, the correct statement is
(1) Between $NH _{3}$ and $PH _{3}, NH _{3}$ is a better electron donor because the lone pair of electrons occupies spherical 's' orbital and is less directional
(2) Between $NH _{3}$ and $PH _{3}, PH _{3}$ is a better electron donor because the lone pair of electrons occupies $s p^{3}$-orbital and is more directional
(3) Between $NH _{3}$ and $PH _{3}, NH _{3}$ is a better electron donor because the lone pair of electrons occupies $s p^{3}$-orbital and is more directional
(4) Between $NH _{3}$ and $PH _{3}, PH _{3}$ is a better electron donor because the lone pair of electrons occupies spherical 's' orbital and is less directional

• A. Between $NH_3\, and\, PH_3 , NH_3$ is a better electron donor because the lone pair of electrons occupies spherical -- orbital and is less directional
• B. Between $NH_3\, and\, PH_3 , PH_3$ is a better electron donor because the lone pair of electrons occupies sps -orbital and is more directional
• C. Between $NH_3\, and\, PH_3 , NH_3$ is a better electron donor because the lone pair of electrons occupies sp3 -orbital and is more directional
• D. Between $NH_3\, and\, PH_3 , PH_3$ is a better electron donor because the lone pair of electrons occupies spherical -- orbital and is less directional

Answer 1

Answer: (C)

$NH_3$ is stronger Lewis base than $PH_3$. In a group of hydrides,
basic strength decreases down the group.