Question

What is the bond angle of a molecule undergoing $s{p^2}$ hybridization?

Answer 1

Hint : VSEPR (valence shell electron pair repulsion theory) gives a basic idea about the shape of a molecule depending upon its electron pair present in the valence shell.
This concept of hybridization was first introduced by Pauling. According to Pauli, the atomic orbitals combine to form a new set of equivalent orbitals which are commonly known as hybrid orbitals.

Complete Step By Step Answer:
Hybridization is used to explain the characteristic shapes of molecules made up of 2 or more atoms.
Any molecule undergoes $s{p^2}$ hybridization, one $s$ orbital and one $p$ orbital combine together to form $s{p^2}$ hybridized orbital which are equivalent in terms of orbital energy.
For example, boron trichloride molecules undergo $s{p^2}$ hybridization.
Boron acts as a central atom of the molecule with electronic configuration $1{s^2}2{s^2}2{p^1}$ .
Boron extends its valency by transferring one electron from $2s$ to $2p$ orbital.
Now the final configuration of boron becomes $1{s^2}2{s^1}2{p^2}$ with three valence.
finally, one $2s$ orbital and two $2p$ orbital of boron undergo hybridization to from $s{p^2}$ hybridized
orbital.
These hybridized orbitals undergoes overlapping with $2p$ orbital of three chlorine atom
to form boron trichloride.
Chlorine atoms are arranged at ${120^ \circ }$ with the central metal atom to form a geometry known as trigonal planar.

molecules undergoing $s{p^2}$ hybridization includes- $B{F_3}$ , $AlC{l_3}$ , ${C_2}{H_4}$ , $N{O_3}^ -$ .
Hence, the bond angle of molecule undergoes $sp^2$ Hybridization is 120 degrees.

Note :
Remember that the total number of hybridized orbitals is always a sum of all the orbital undergoes hybridization. Hybrid orbital rearrange into a specific angle to form a stable arrangement. Angle in different molecules changes with change in hybridization for example molecule undergo $sp$ hybridization form angle of ${180^ \circ }$ while ${109.5^ \circ }$ angle is formed by $s{p_3}$ hybridized molecules.