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Recrystallization

The goal of the recrystallization procedure is to obtain purified material with a maximum recovery. For each of the following situations, explain why this goal would be adversely affected.

a) In the solution step, an unnecessarily large volume of solvent is used.
b) The crystals obtained after filtration are not washed with fresh cold solvent before drying.
c) The crystals obtained after filtration are washed with fresh hot solvent before drying.
d) A large quantity of decolorizing agent is used.
e) Crystals are obtained by breaking up the solidified mass of an oil that originally separated from the hot solution.
f) Crystallization is accelerated by placing the flask of hot solution in an ice-water bath.

Solution Preview

a) If too much solvent is used, crystallization will not occur fully as some of the pure compound will tend to remain in solution due to excess solvation rather than precipitating out of solution.

b) If not washed with cold solvent, some ...

Solution Summary

The goals of recrystallization procedures are given. The quantity of decolorizing agents are examined.

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