Question

Which of the following will have a meso-isomer also ?

• A. $ 2 $ - chlorobutane
• B. $ 2 $ , $ 3 $ - dichlorobutane
• C. $ 2 $ , $ 3 $ - dichloropentane
• D. $ 2 $ - hydroxypropanoic acid

Answer 1

Answer: (B)

One asymmetric carbon atom, forms $d$- and $l$-optical isomers.
(b) Two asymmetric carbon atoms, forms $d$-, $l$-and meso forms.

Meso due to internal compensation

Two asymmetric carbon atoms but does not have symmetry. Hence, meso form is not formed.

One asymmetric carbon atom, meso form is not formed.