Question

What is the relationship between the specific rotation of (2S ,3S)-dibromopentane and (2R, 3R)-dibromopentane?

A) It is different in magnitude and opposite in sign
B) it is equal in magnitude and have the same sign
C) it is zero
D) it is equal in magnitude but opposite in sign
E) It is not possible to predict the specific rotation

Answer 1

D) it is equal in magnitude but opposite in sign

Step-by-step explanation:

The compounds (2S ,3S)-dibromopentane and (2R, 3R)-dibromopentane are a pair of enantiomers.

Enantiomers are stereoisomers that that are mirror images of each other and rotate plane polarized light. The magnitude of rotation of plane polarized light is known as specific rotation of the compound measured in degrees.

Enantiomers have the same magnitude of specific rotation but opposite in sign. This is because one enantiomer rotates plane polarized light to the left while the other rotates plane polarized light to the right.