The hybridisation state of central atom in H2O, SF6 and PCI5 molecules respectively are:

The correct answer is- sp3, sp3d2 and sp3d

Concept:

Hybridization- Hybridization is defined as the concept of mixing of two atomic orbitals to give rise to a new hybridized orbital.

• The atomic orbitals having comparable energies are mixed together in hybridization.
• The new orbital formed has different energy and shape.
• The new orbital formed is known as a hybrid orbital.
• Hybridization happens only during bond formation and not in an isolated gaseous atom.
• The shape of the molecule can be predicted if the hybridization of the molecule is known.

Types of hybridization- Based on the types of orbitals involved in mixing, the hybridization can be classified as -

sp, sp², sp³, sp³d, sp³d², sp³d³

How to calculate Hybridization:

1. Find the valence electrons on an atom whose hybridization is to be determined.
2. Calculate the number of bonded atoms.
3. Calculate the number of lone pairs.
4. Calculate the steric number.
5. On the basis of steric number, the hybridization of an atom can be determined.

Steric Number = No. of atoms bonded + lone pairs of electrons of an atom

Table to determine the hybridization

Explanation:

In H₂O -

• The central atom is O.
• Bonded atoms = H
• Valence electrons of O = 6
• No. of atoms bonded to O = 2
• No. of lone pairs of O in H₂O = 2
• Steric No. of O in H₂O = 4
• Therefore, hybridization of O in H2O = sp³ 

​In SF₆ -

• The central atom is S.
• Bonded atoms = F
• Valence electrons of S = 6
• No. of atoms bonded to S = 6
• No. of lone pairs of S in SF6 = 0
• Steric No. of S in SF6 = 6
• Therefore, hybridization of S in SF₆ = sp3d²

​In PCl₅ -

• The central atom is P.
• Bonded atoms = Cl
• Valence electrons of P = 5
• No. of atoms bonded to P = 5
• No. of lone pairs of P in PCl5 = 0
• Steric No. of P in PCl5 = 5
• Therefore, hybridization of P in PCl5 = sp3d

Therefore, the hybridization of the central atom in H2O- sp3, SF6 - sp3d2, PCl5 - sp3d