Question

5.41 Predict the value for the specific rotation of the following compound. Explain your answer. -OH НО. 5.42 The specific rotation of (S)-2-butanol is +13.5. If 1.00 g of its enantiomer is dissolved in 10.0 mL of ethanol and placed in a sample cell with a length of 1.00 dm, what observed rotation do you expect? 5.43 The specific rotation of l-alanine in water (at 25°C) is +2.8. A chemist prepared a mixture of l- alanine and its enantiomer, and 3.50 g of the mixture was dissolved in 10.0 mL of water. This solution was then placed in a sample cell with a pathlength of 10.0 cm and the observed rotation was +0.78. Calculate the % ee of the mixture.

Answer 1

The answer is given in the attachment .

X - 79112 specular weight of (9) Bukamel = 74129 mo/? 0.1-00g formple in some solchon = (1.00 °M21:35M. . Observed rotation- []=[], dxC = 43.5x3.00% 1,35745 :: 127= 18-23 ] -- Answers 5:43 The % enombiemerné excess = (band) 2000'l-el. Now, the theoritical mass of L-alanine = 89.09 gmolt. - loncenhalion = 3.50 x 1000 M=3.93 M. 89:09 10 am alam. Q] - 2].*d*6 = +2.8 *10*3.93 i B] - 11.004. Enam biomene emers ee- 4 x100%. Enamhomenie excusa per te X100= Fl. I Answer] :76= bem plool. 2106% t-d=7 dtl=1004. a (= 53.5%, de 46.5% 1.004