Question

What is the hybridization of phosphorus in $PC{l}_5$?

Answer 1

In $PC{l}_5$, phosphorus undergoes $s{p}^{3}d$ hybridization and has trigonal bipyramidal geometry in gaseous and liquid states.
It has three equatorial $P-Cl$ bonds and two axial $P-Cl$ bonds. Since two axial $P-Cl$ bonds are repelled by three bond pairs while three equatorial $P-Cl$ bonds are repelled by two bond pairs, therefore, axial bonds are longer than equatorial bonds.