Question

Which of the following does not show geometrical isomerism?(a) 1,2-dichloro-1-pentene (b) 1,3-dichloro-2-pentene(c) 1,1-dichloro-1-pentene(d) 1,4-dichloro-2-pentene

Answer 1

c) 1,1-dichloro-1-pentene

Answer 2

Answer:

(c) 1,1-dichloro-1-pentene is the correct answer.

Explanation:

Two compunds are said to be geometrically isomeric when they have same chemical formula but different geometrical symmetry.

Restricted rotation should be there for geometrical isomerism.

There should be 2 different groups on left hand side and right hand side.

Geometrical isomerism is also known as cis trans isomerism or EZ isomerism.

c) 1,1-dichloro-1-pentene.

It has formula C5H8Cl2.

The carbon is double bonded.

But the 2 carbons are not different.

The Cl group is same.

Hence C5H8Cl2 does not show geometrical isomerism.

Hence, (c) 1,1-dichloro-1-pentene is the correct answer.