Question

Which of the following statement(s) is/are correct for compound having one chiral centre?

• A. R/S configuration of fischer projection does not change if the molecule is rotated by ${180}^o$ in the plane of the paper
• B. Rotation of fischer projected molecule by ${90}^o$ in the plane of paper will give a identical molecule
• C. R/S configuration doesn't change by an even interchange of groups in fischer projection
• D. Odd interchange of groups in fischer projection will gives it enantiomeric pair

Answer 1

Answer: (A), (C), (D)

Odd interchange of groups in fischer projection will gives it enantiomeric pair

For a fischer projection molecule having only one chiral centre, configuration doesn't change on rotating the molecule by 180 degree in the plane of the paper. It gives a identical molecule.
But on rotating the molecule by 90 degree in the plane of the paper will gives its enantiomeric pair.




Also, configuration doesn't change by an even interchange of groups per chiral atom.
Example:

But, configuration changes by an odd interchange of groups per chiral atom.
Example:

Thus, statement (a), (c) and (d) are correct.