Answer questions and show your work clearly. No credit will be given for or ambi
ID: 537181 • Letter: A
Question
Answer questions and show your work clearly. No credit will be given for or ambiguous work. In the experiment of extraction from methylene chloride solution of benzoic acid and acetanilide, benzoic acid (C_6 H_5 COOH) was extracted with a solution of sodium hydroxide. Please write the chemical equation for the step to mix two solutions, methylene chloric (CH_2 Cl_2) solution with aqueous solution of sodium hydroxide (NaOH). Which chemicals are in both layers? Please identify them with the names and lagers. What can you do if you do not know which layer is the organic layer the aqueous layer is an extraction experiment? Addition of HCl(aq) to the aqueous layer of extract resulted white precipitate. Please write the chemical equation of this step.Explanation / Answer
1) If the mixture of acetanilide and benzoic acid mixed with CH2Cl2 and NaOH, the organic compound acetanilide get soluble in CH2Cl2 due to non-polar interactions while benzoic acid dissolves in NaOH due to the formation of a salt(sodium benzoate) which is readily soluble in aqueous layer.
C6H5-COOH + NaOH ----> C6H5-COONa + H2O
2) On shaking the mixture of acetanilide and benzoic acid with CH2Cl2 and NaOH, acetanilide soluble in organic layer and present in the bottom while benzoic acid soluble in NaOH and present in aqueous layer on the top
3) It can be done by adding a drop of water with the help of pippette. If the aqueous layer is on the bottom the drop of water will sink through the top layer and increases the volume of the bottom layer. If aqueous layer is on the top, the top layer will increase its volume
4) To the auqeous layer containing benzoic acid in the form of salt, if HCl is added the benzoic acid will precipitate out due to the following reaction
C6H5-COONa + HCl ----> C6H5-COOH + NaCl