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1. (+)-Tartaric acid has a specific rotation of +12°. Calculate the specific rot

ID: 933111 • Letter: 1

Question

1. (+)-Tartaric acid has a specific rotation of +12°. Calculate the specific rotation of a mixture of 67 % (+)-tartaric acid and 33 % (-)-tartaric acid.

2.

A pharmaceutical chemist is working on a new large-scale synthesis for the popular pain reliever, naproxen. To be useful, however, the synthesis must be highly stereospecific, for whereas the (S) isomer of naproxen is a safe pain-reducing drug, the (R) isomer is a potentially harmful liver toxin.

To determine the purity of the synthesized product, the chemist dissolves 78.2 mg of obtained product in 2.30 mL of solvent and measures the optical activity of the sample in a 5.00-cm tube, observing a value of +1.03°. A 0.500 g/mL solution of pure (S) isomer is measured under identical conditions, giving a value of + 16.5°.

What is the number of degrees for the specific rotation of the (S) enantiomer?

Explanation / Answer

1. (+)-Tartaric acid has a specific rotation of +12°. Calculate the specific rot