Question
Which of the following acid does not exhibit optical isomerism?
A.
Maleic acid
B.
$$\alpha $$ - amino acid
C.
Lactic acid
D.
Tartaric acid
Answer :
Maleic acid
Solution :
Only those compounds exhibit optical isomerism, which have chiral centre and/or absence of symmetrical elements. ( Chiral carbon is the carbon in which all the four valencies are satisfied by four different groups. )
Thus, maleic acid does not exhibit optical isomerism.
NOTE
If $$R = H,$$ the $$\alpha $$ - amino acid is achiral.
Only those compounds exhibit optical isomerism, which have chiral centre and/or absence of symmetrical elements. ( Chiral carbon is the carbon in which all the four valencies are satisfied by four different groups. )
Thus, maleic acid does not exhibit optical isomerism.
NOTE
If $$R = H,$$ the $$\alpha $$ - amino acid is achiral.