1. An aqueous solution consisting of 50 mg of butanoic acid 5 mL of water is to be extracted 3 times with 1.0 mL ether. If the distribution coefficient for this extraction is equal to 8.5, how much acid will remain in the aqueous layer after the three extraction?   

2. In isolating the neutral component of your unknown, an ether solution of the unknown is obtained, and dry compound obtained by evaporating the ether with either a stream of nitrogen or by placing the solution in your drawer. Why is this preferred to heating the solution on a heating block to evaporate the ether?