Question

The number of geometrical isomers possible for the compound, CH$_3$CH = CH - CH = CH$_2$ is:

• A. 2
• B. 3
• C. 4
• D. 6

Hint:

For cis-trans isomerism, each carbon in the double bond must have two different substituents.

Answer 1

The Correct Option is A

Step 1: Identifying the Double Bonds
The given compound has two double bonds.
The key factor in determining geometrical isomerism is whether each double bond has two different substituents.
Step 2: Checking for Geometrical Isomerism
The double bond at position \( {C}_2 - {C}_3 \) has two different groups, allowing cis-trans isomerism.
The double bond at \( {C}_4 - {C}_5 \) has identical hydrogen atoms, preventing cis-trans isomerism.
Step 3: Number of Isomers
Only one double bond exhibits cis-trans isomerism.
Therefore, only two geometrical isomers exist.
Thus, the correct answer is (A).