A pure sample of (S)-phenylalanine has a specific rotation of +70°. A mixture of the two enantiomers of
phenylalanine has a specific rotation of +7.0°. What are the percentages of the S and R enantiomers in the
mixture?
A. 95% S, 5% R
B. 90% S, 10% R
C. 55% S, 45% R
D. 52.5% S, 47.5% R
and why