Question

$A$:

Discuss the concept of hybridisation. What are its different types in a carbon atom.

$B$:

What is the type of hybridisation of carbon atoms marked with star.

A. B.C.D.E.

Answer 1

$A$:

Concept of hybridisation:

Hybridisation is the process of intermixing of the orbitals of slightly different energies so as to redistribute their energies, resulting in the formation of new set of orbitals of equivalent energies and shape. New orbitals formed are called hybrid orbitals.

For example, when one $2s$ and three $2p$-orbitals of carbon hybridise to form four new $s{p}^3$ hybrid orbitals.

The main features of hybridisation are as under:

• The number of hybrid orbitals formed is equal to the number of the atomic orbitals that get hybridised.
• The hybridised orbitals are always equivalent in energy and shape..
• The hybrid orbitals are more effective in forming stable bonds than the pure atomic orbitals.
• These hybrid orbitals are directed in space in some preferred directions to have minimum repulsions between electron pairs hence acquire a stable arrangement.
• Therefore, the type of hybridisation indicates the geometry of the molecules.

Types of hybridisation in a carbon atom

• In carbon compounds, if carbon is linked to carbon through a triple bond and with any other atom with a single bond $(-C\equiv C-)$, then there will be $\sigma$ bonds which carbon is forming, e.g., alkynes, then it is sp hybridised.
• In carbon compounds, if carbon is linked to carbon through a double bond and with other two atoms with a single bond.There will be $3\sigma$ bonds which carbon is forming, e.g., alkenes, then it is $s{p}^2$ hybridised.
• In carbon compounds, if carbon is linked to carbon through a single bond and with other three atoms with a single bond.There will be $4\sigma$ bonds which carbon is forming, e.g., alkanes, then it is $s{p}^3$ hybridised.

$B$:

Marked carbon atoms	Hybridization
	$s{p}^2,s{p}^2$
	$s{p}^3$
	$s{p}^2$
	$s{p}^3$
	$sp$