JEE Main 2024 — Chemical Bonding and Molecular Structure Question with Solution

${\mathrm{PF}}_5$ involves sp³d hybridisation and hence has trigonal bipyramidal structure.

In ${\mathrm{PCl}}_5$  the central atom is surrounded by five bond pairs and no lone paris.
Hybridisation of central atom in ${\mathrm{PCl}}_5$ molecule is sp³d giving trigonal bipyramidal shape.

In $\left[\mathrm{Fe}(\mathrm{CO}{)}_5\right]$, oxidation state of CO is zero.

It has hybridisation =dsp³.

So it has trigonal bipyramidal geometry.

${\mathrm{BrF}}_5;$ square pyramidal

${\left[{\mathrm{PtCl}}_4\right]}^{-2};$ square planar

${\mathrm{BF}}_3;$ Trigonal planar.

Hence the answer is $3$