The specific rotation of dextrorotatory tartaric acid is +12.7 degrees. A mixture of dextrorotatory and levorotatory tartaric acid has a specific rotation of +6.35 degrees. What is the optical purity of the mixture?

Question

Quizplus · Accepted Answer

The optical purity is calculated as the observed rotation divided by the rotation of the pure enantiomer, times 100. Here, +6.35 / +12.7 * 100 = 50%. This means the mixture is 50% optically pure, indicating an equal mixture of dextrorotatory and levorotatory forms.

The Specific Rotation of Dextrorotatory Tartaric Acid Is +12