Question

A compound of molecular formula C₇H₁6 shows optical isomerism, compound will be

• A. 2,3-Dimethylpentane
• B. 2,2-Dimethylbutane
• C. 3-Methylhexane
• D. None of the above

Hint:

Presence of at least one asymmetric (chiral) carbon is necessary for optical activity.

Answer 1

The Correct Option is C

Step 1: Optical isomerism requires a chiral carbon atom (attached to four different groups). Step 2: \beginitemize • 2,3-Dimethylpentane — has plane of symmetry ⟹ achiral • 2,2-Dimethylbutane — highly symmetrical ⟹ achiral • 3-Methylhexane — carbon at position 3 is attached to four different groups ⟹ chiral \enditemize Step 3: Hence, only 3-Methylhexane shows optical isomerism.