試題詳解

11. A pure sample of (S)-phenylalanine has a specific rotation of +70^o . A mixture of the two enantiomers of phenylalanine gives a specific rotation of -7.0^o . What are the percentages of the S and R enantiomers in the mixture?
(A) 75 % S, 25 % R
(B) 65 % S, 35 % R
(C) 55 % S, 45 % R
(D) 45 % S, 55 % R
(E) 35 % S, 65 % R