chem
posted by Jason .
An optical rotation study gives a result of alpha=+140 degrees. Suggest a dilution experiment to test whether the result is indeed +140 degrees, and not 220 degrees.
could polarimetry experiment be used to find the r and s isomer?

Yes, I think it can. This problem has been posted before and I suggested diluting the sample by a factor of 10 and measuring the rotation. If the original was indeed 140 degrees, then the new measurement would show 14.0 degrees. If the original measurement was 220 degrees, the new measurement would be 22.0 degrees. There would be no confusion between +14 and 22. Check my thinking.