Question

Which of the following(s) is/are an optically active compound ?

• A. Alanine
• B. $1,3$ - Diphenyl propadiene
• C. Meso - tartaric acid
• D. Glyceraldehyde

Answer 1

Answer: (A), (B), (D)

Glyceraldehyde

(a). Alanine
It has a single chiral carbon, hence, it shows optical activity.

(b). $1,3$ - Diphenyl propadiene
It is an even cumulenes where the terminals are not in a same plane and the terminals attached to the $s{p}^2$ carbons are different. Hence, it does not have any plane of symmetry. Thus, it shows optical activity.

(c). Meso- tartaric acid
Meso compounds have plane of symmetry and it is optically inactive due to internal compensation.

(d) Glyceraldehyde
It has a single chiral centre, hence, it is optically active.