Question

1.During an extraction, a solute (S) will partition itself between two immiscible solvents phases [S (solvent 1)   S (solvent 2)] with a partition coefficient defined as If solute X is 1.5 times more soluble in solvent 2 than it is in solvent 1 it has a partition coefficient of 1.5. Suppose a reaction mixture, when diluted with water, afforded 300 mL of an aqueous solution of 30 g of the reaction product malononitrile [CH₂(CN)₂], which is to be isolated by extraction with ether. The solubility of malononitrile in ether at room temperature is 20.0 g/100 mL, and in water is 13.3 g/100mL. The ratio of these quantities is equal to the partition coefficient, k, which equals

What percent of malononitrile would be recovered by extraction of (a) three successive 100-mL portions of ether and (b) one 300-mL portion of ether? SHOW WORK (Can be written in pen and attached to report). Suggestion: For each extraction, let x equal the weight extracted into the ether layer. In part (a), for the first of the three extractions, the concentration of malononitrile in the ether layer is x/100 and in the water layer is (30-x)/300. Note in the 2^nd of the 3 100-mL extraction the grams of malononitrile is no longer 30.

Answer 1