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1. How would the following actions effect both the yield AND the purity of your

ID: 888518 • Letter: 1

Question

1. How would the following actions effect both the yield AND the purity of your recrystallized trans-1,2-dibenzoyl ethylene

a. The dichloromethane solution is not treated with activated carbon

b. The crude crystals are not completely dissolved in the dichloromethane before filtering the activated carbon.

c. The 1 ml dichloromethane rinse is not applied to your flask and filter column

d. The crystals are not completely dissolved in hot ethanol before recrystallizing the trans-1,2-dibenzoylethylene

2. Based on the structures of cis- and trans-dibenzoylethylene, which isomer would you expect to be more polar? What physical properties would be affected by the differences in polarity between the two isomers?

Explanation / Answer

C&D are correct

2. cis form is more polar because dipole moment is not zero but trans dipolmement is zero

melting point and boiling point, stability