Question

Why is ${\mathrm{PCl}}_5$ Lewis acid?

Answer 1

Lewis Acid:

• Any species (molecule or ion) that can accept a pair of electrons is referred to as a Lewis acid.
• .In the valence shell of ${\mathrm{PCl}}_5$ , there is an empty d orbital.

Lewis structure of ${\mathrm{PCl}}_5$.

• And also high electronegative chlorine atoms attract the electron cloud towards itself and Phosphorus here becomes more electron deficit.
• Phosphorus in Phosphorous pentachloride $\left({\mathrm{PCl}}_5\right)$ takes electrons easily from other compounds. As a result, it is classified as a Lewis acid.