Specific Rotation of Chiral Molecules

[Cyberchicken]

Homework Statement

Why may the specific rotation of a sample of (R)-(+)-limonene be less than the literature value of (R)-(+)-limonene. Assume that there are so (S) enantiomers present.

Homework Equations

The Attempt at a Solution

There are no (S) enantiomers, but there are some molecules of methylene chloride mixed into the sample that was analyzed. But since these are achiral, I don't understand why they should affect the rotation of the limonene.

 

[Ygggdrasil]

When you calculate the specific rotation of a sample, what values do you need to know? Would the presence of solvent affect any of those values?

 

[Cyberchicken]

When you calculate the specific rotation of a sample, what values do you need to know? Would the presence of solvent affect any of those values?

The solvent used was ethanol, so that should not affect the optical activity. Are there any other factors which would affect it? Like the presence of methylene chloride perhaps? And why would it affect it?

 

[Ygggdrasil]

Again, think about how you calculate the specific rotation of a sample. You place your sample in the polarimerter and obtain the angle by which your sample rotated the light. How do you calculate the specific rotation from that value?