Question

Which of the following statements is correct for the sigma and the pi bonds formed between two carbon atoms?

• A. Free rotation of atoms about a sigma bond is allowed but not in the case of pi bond
• B. Sigma bond determines the direction between carbon atoms but a pi bond has no primary effect in this regard
• C. Sigma bond is stronger than a pi bond
• D. All of the above

Answer 1

The correct option is D All of the above

a) Sigma bonds are formed by the axial overlap of orbitals whilst the pi bonds are formed by the sideways or lateral overlap of orbitals. Thus, free rotaion is allowed only for sigma bonds.

b) Sigma bond determines the direction between the carbon atoms because it is formed by the head on overlapping of the constituting atomic orbitals along the internuclear axis. And only after the formation of sigma bond, pi bond is formed.

c) The extent of overlapping is more in case of sigma bonds as compared to pi bonds and there is greater electron density between the two nuclei along the internuclear axis. Thus, a sigma bond is stronger than a pi bond.