Question

The formation of $P{H}_4^{+}$ is difficult compared to $N{H}_4^{+}$ because:

• A. lone pair of phosphorous is optically inert.
• B. lone pair of phosphorous resides in almost pure p – orbital
• C. lone pair of phosphorous resides in sp³ orbital
• D. lone pair of phosphorous in almost pure s – orbital

Answer 1

The correct option is D

lone pair of phosphorous in almost pure s – orbital

$+H^{+}⟶P{H}_4^{+}$

According to Drago’s rule lone pair on phosphorous resides in almost pure – s – orbital, hence due to non – directional nature, its overlapping tendency is greatly reduced in comparison to a lone pair present in hybrid orbital, which is directional as present in