Question

A. Magnesium sulfate is the drying agent used in this experiment. Why is it necessary to use a drying agent before removing the organic solvent on the rotary evaporator?

b. Adding sodium chloride can often help cause emulsions to breakdown and separate in to distinct layers. Use the principles of solubility from experiment 1 to explain why this works.

Two Part Question: Someone already answered this but I could not read it at all

Answer 1

A) This is done in oder to remove the traces of water molecules which remains in the organic phase , and skipping this process results in leaching of extracted compound in water, during evaporation( as water is having high boiling point and thus evaporated in last) and thus lower yield extracted compound.

B) emulsions are non polar substances surrounded by polar substances like water. And, when NaCl is added in relative amounts( according to its solubility in water) it attracts the water molecules thus acts acts as a barrier in formation of emulsion and forms a two immiscible layer ie aqueous and organic out of the emulsion.