Which of the following molecules has an R configuration?
C) both a and b
D) neither a nor b

Question

Which of the following molecules has an R configuration?
C) both a and b 
D) neither a nor b

Quizplus · Accepted Answer

The R and S configurations are determined by the sequence of priority of the substituents around a chiral center. To determine the configuration, we assign priority to the substituents based on their atomic number. In molecule B, the highest priority group (Cl) is in the back, the second-highest priority group (OH) is on the left, and the third-highest priority group (H) is on the right. This means that the fourth priority group (CH3) is pointing towards us. When we follow the priority sequence from 1 to 2 to 3, if the sequence is clockwise, then the configuration is R. In this case, the sequence is clockwise, so the configuration is R. Therefore, the correct answer is B. Molecule A is not chiral because it has a plane of symmetry, and thus cannot have an R configuration.

Which of the Following Molecules Has an R Configuration