(+)-Tartaric acid has a specific rotation
Of +12.0°.

Calculate ...

Question

(+)-Tartaric acid has a specific rotation 
Of +12.0°.

Calculate the specific rotation of a mixture of 68% (+)-tartaric acid and 32# (-)—tartaric acid.

Accepted Answer

Hey everyone. Let's solve this problem and says a mixture consists of 20% of plus Penton to all and 80% of minus Penton to all determine the specific rotation of the mixture. If the specific rotation of pure minus Penton tool is 13 degrees. So, we're trying to find the specific rotation of the mixture described here. If we know the specific rotation of pure minus Penton to all. Okay, well we have 80% of minus Penton to all In 20% of plus. So 20% of the minus can cancel out that 20% of the plus. And if we subtract, those that gives us 60% excess in an tumor of the minus Penton tool, so 80% of the minus minus 20% of the plus And that gives us 60% excess Penton to all. Okay, And we know the specific rotation of pure minus is 13°. So, if we use .60, the decimal of 60%, that will be our optical purity. Right? So taking 60% of the rotation of pure minus Penton. All right. Since we only have 60% of the minus in our actual mixture, 60% of the 13° will give us 7.8° and that will be the specific rotation of our mixture. Okay, which makes be the correct answer. That's it for this problem. I hope this video is helpful. And thanks for watching

(+)-Tartaric acid has a specific rotation Of +12.0°. Calculate the specific rotation of a mixture of 68% (+)-tartaric acid and 32# (-)—tartaric acid.

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