Organic chemistry question about extraction lab...?
Procedure:
Place 2.0 g of the mixture of sucrose, acetylsalicylic acid andacetanilide into a 125 mL Erlenmeyer flask.
Add 50 mL of methylene chloride (dichloromethane) and dissolve asmuch of the solid as possible.
Remove the insoluble sucrose via gravity filtration using flutedfilter paper. Allow to dry until the next lab period.
Add the methylene chloride solution to the separatory funnel andextract it with two 25 mL portions of 5 % sodium bicarbonate(aqueous).
Place the combined aqueous layers into a 400 mL beaker and addenough concentrated hydrochloric acid to make it very acidic (lessthan pH of 2) – approximately 10 mL
Allow the solid to crystallize from the aqueous layer. Chilling inan ice bath may be required.
When lots of solid has been formed, collect the solid by vacuumfiltration. Wash the solid with approximately 5 mL of coldwater
Allow the solid to dry open until the next lab period.
Dry the organic layer (methylene chloride) over anhydrous sodiumsulfate.
Decant the solvent from the drying agent (or gravity filter throughfluted filter paper) into a clean, dry a pre-weighed 100 mLround-bottom flask.
Evaporate the solvent using rotary evaporation and allow theresidue to dry open over the week.
The following lab period, weigh all 3 solids, take the meltingpoints of all 3 solids and calculate the percent composition of theoriginal solid.

Drying agents:
Equations for drying agents:
MgSO4 (s) + 7 H2O(l)  MgSO4.7H2O(s)
CaSO4(s) + 2 H2O(l)  CaSO4.2H2O(s)
CaCl2(s) + 6 H2O(l)  CaCl2.6H2O(s)
Na2SO4(s) + 7 H2O(l)  Na2SO4.7H2O(s)

1.      The original organic solutionwas extracted two times with aqueous sodium bicarbonate. After theextraction, what compound(s) were in the organic layer? Whatcompound(s) were in the aqueous layer?

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2.      Assume that bothacetylsalicylic acid and acetanilide are soluble in diethyl ether,and that diethyl ether was used in place of the methylene chloride.Would the ether layer be the bottom layer in the separatory funnelor the top layer? Explain your answer.

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3.      Assume that bothacetylsalicylic acid and acetanilide are soluble in methanol, andthat methanol was used in place of the methylene chloride. Whatproblem(s) might occur during the extractions? (Careful, this is atrick question.)

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4.      Historically, the solid residuethat is left after the methylene chloride solution is evaporatedhas a lower melting point that its literature value, due toimpurities. Explain what impurities are present and why.

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