17.A particular reaction produces the following two alcohols in a ratio of95:5 95:5 The enantiomer A)100 D)85 E)none of the above Ans:C 18.(S)-Naproxen,[alp=+66,is an analgesic (pain reliever),while its enantiomer is toxic Say that you were given a solution that contains 1 g of Naproxen in 20 mL of liquid,but the optical purity is not specified.You place it in a polarimeter tube(10 cm)and get a reading of+3.3 from the polarimeter.What is the percent optical purity of the sample B)100 C)0 D)10 E)75 19.Which of the following molecules have the S configuration? H H H.cBr H火 Et (CH3)C" iso-propyl Br B)L,ⅢC)Ⅲ，IV D)I,II,IV E)all of the above 20.What(R)or(S)stereochemistry is proper for the following molecule? HC、/ cH,CH, CiH A)(2R.3R) B)(2R,3S9 C)(2S,39 D)(25.3R)E)none of the above Ans:B Page7 Page 7 17. A particular reaction produces the following two alcohols in a ratio of 95:5. OH OH 95 : 5 The enantiomeric excess (% ee) is: A) 100 B) 95 C) 90 D) 85 E) none of the above Ans: C 18. (S)-Naproxen, [α]D = + 66°, is an analgesic (pain reliever), while its enantiomer is toxic. Say that you were given a solution that contains 1 g of Naproxen in 20 mL of liquid, but the optical purity is not specified. You place it in a polarimeter tube (10 cm) and get a reading of + 3.3° from the polarimeter. What is the percent optical purity of the sample? A) 50 B) 100 C) 0 D) 10 E) 75 Ans: B 19. Which of the following molecules have the S configuration? H Br H3C F (CH3)3C H H iso-propyl H3C Et D Br H I II III IV A) I, II B) I, III C) III, IV D) I, II, IV E) all of the above Ans: A 20. What (R) or (S) stereochemistry is proper for the following molecule? H3C C C CH2CH3 H Br Cl H 5 4 3 2 1 A) (2R,3R) B) (2R,3S) C) (2S,3S) D) (2S,3R) E) none of the above Ans: B