(-)-Cholesterol has a specific rotation of -32o. A mixture of ( )- and (-)-cholesterol was analyzed by polarimetry, and the obse

Answer:

The composition of (+)-cholesterol is 71.88%

The composition of (-)-cholesterol is 28.12%

Explanation:

Assuming 1 gram of the sample is dissolved in 1mL of water and the sample cell was 1dm long.

Enantiomeric excess refers to the amount of pure enantiomer present in a sample. The calculation follows:

ee = [α]mixture / [α]pure enantiomer.

With substitutions:

ee = 14° / 32°×100 = 43.75%

Given that the sample reflects 14°, there is an excess of (+)-cholesterol and 56.25% represents a 1:1 mixture of the enantiomers.

This indicates the percent composition of the enantiomers is:

(+)-cholesterol = 43.75% + 56.25%/2 = 71.88%

(-)-cholesterol =  56.25%/2 = 28.12%