Question

Optical activity of an enantiomeric mixture is +12.6° and the specific rotation of (+) isomer is +30°. The optical purity is _______%.

Answer 1

Correct Answer: 42

To determine the optical purity of the enantiomeric mixture, we utilize the formula for optical purity (OP):

Optical Purity (OP) = (Observed Rotation / Specific Rotation of Pure Enantiomer) × 100%

Given:

• Observed Rotation = +12.6°
• Specific Rotation of (+) isomer = +30°

We substitute these values into the formula:

OP = (+12.6° / +30°) × 100%

Calculating this gives:

OP = 0.42 × 100% = 42%

Thus, the optical purity of the mixture is 42%.

Checking against the provided range (42,42): the calculated optical purity of 42% matches exactly with the expected range.