Question

Distinguish between a sigma and a pi bond.

Answer 1

The following are the differences between sigma and pi-bonds:

Sigma $(\sigma)$ Bond	Pi ${(\pi)}$ Bond
(a) It is formed by the end to end overlap of orbitals.	It is formed by the lateral overlap of orbitals.
(b) The orbitals involved in the overlapping are $s-s, s-p$ ,or $p-p$.	These bonds are formed by the overlap of$p-p$ orbitals only.
(c) It is a strong bond.	It is weak bond.
(d) The electron cloud is symmetrical about the line joining the two nuclei.	The electron cloud is not symmetrical.
(e) It consists of one electron cloud, which is symmetrical about the internuclear axis.	There are two electron clouds lying above and below the plane of the atomic nuclei.
(f) Free rotation about σ bonds is possible.	Rotation is restricted in case of $pi-bonds$.