Question

The number of geometrical isomers in case of a compound with the structure $C{H}_3-CH=CH-CH=CH-C_2{H}_5$ is:

• A. $4$
• B. $3$
• C. $2$
• D. $5$

Answer 1

The correct option is A $4$

When a compound has n double bonds and ends of a polyene are different, the number of geometrical isomers = $2^n$
The given compound has two double bonds and two ends are different, ${CH}_3$ and $C_2{H}_5$.
Therefore the number of geometrical isomers in the given polyene is $2^n$ =$2^2=4$
conclusion: hence thje option (A) is correct.