Question

Reason for geometrical isomerism by 2-butene is:

• A. Chiral carbon
• B. Free rotation about single bond.
• C. Free rotation about double bond.
• D. Restricted rotation about double bond.

Answer 1

The correct option is D

Restricted rotation about double bond.

Compound will exhibit geometrical isomerism if it fulfills the following two conditions:

$\to$There should be frozen rotation about two adjacent atoms in the molecule

$\to$Both substituents on each carbon should be different about which rotation is frozen.