Chapter 21, Problem 68A

Interpretation Introduction

Interpretation:

The effect on polarized light by optical isomers needs to be determined.

Concept introduction:

Two mirror image representations are possible for a molecule having chiral center in its structure. If the mirror images are non-superimposable to each other then, they are said to be optical isomers.

Explanation of Solution

On passing a polarized light through a sample cell containing optical isomer, then one isomer will rotate the light in one direction whereas the second isomer will rotate the light in other direction. The rotation of light is clockwise when the isomer is D-isomer whereas for L-isomer the rotation of light is counter-clockwise.

No rotation in polarized light is observed when there is an equal or racemic mixture of optical isomers are present that results in cancelling the rotation out.