5. Chirality
Enantiomeric Excess
11PRACTICE PROBLEM
Addition of a chiral molecule to the catalytic reduction of pentan-2-one produces a slightly optically active product. Determine the percentage of (+)-pentan-2-ol and (−)-pentan-2-ol formed in the reaction if the specific rotation of the product is +0.54º. (The rotation of pure (−)-pentan-2-ol at the same condition is 13.0º)
A. (+)-pentan-2-ol = 0.54 % and (−)-pentan-2-ol = 99.46 %
B. (+)-pentan-2-ol = 47.9 % and (−)-pentan-2-ol = 52.1 %
C. (+)-pentan-2-ol = 52.1 % and (−)-pentan-2-ol = 47.9 %
D. (+)-pentan-2-ol = 95.85 % and (−)-pentan-2-ol = 4.15 %
Addition of a chiral molecule to the catalytic reduction of pentan-2-one produces a slightly optically active product. Determine the percentage of (+)-pentan-2-ol and (−)-pentan-2-ol formed in the reaction if the specific rotation of the product is +0.54º. (The rotation of pure (−)-pentan-2-ol at the same condition is 13.0º)
A. (+)-pentan-2-ol = 0.54 % and (−)-pentan-2-ol = 99.46 %
B. (+)-pentan-2-ol = 47.9 % and (−)-pentan-2-ol = 52.1 %
C. (+)-pentan-2-ol = 52.1 % and (−)-pentan-2-ol = 47.9 %
D. (+)-pentan-2-ol = 95.85 % and (−)-pentan-2-ol = 4.15 %