Question

Outlined below are statements describing the general procedure followed during the purification of a solid by recrystallization. Order the process from start to finish:

a) Selection of an appropriate solvent for recrystallization.
b) Dissolution of the solid in the minimum amount of hot solvent.
c) Cooling the solution to allow crystals to form.
d) Filtration of the crystals from the solvent.
e) Washing the crystals with a cold solvent.
f) Collection and drying of the purified crystals.

Provide a logical and step-by-step sequence for the recrystallization process based on the statements provided.

Answer 1

The recrystallization process involves selecting an appropriate solvent, dissolving the solid in it, cooling to form crystals, filtering to separate crystals, washing to remove impurities, and drying the purified crystals.

Step-by-step explanation:

Procedure of Solid Purification by Recrystallization

1. Selection of an appropriate solvent for recrystallization.
2. Dissolution of the solid in the minimum amount of hot solvent.
3. Cooling the solution to allow crystals to form.
4. Filtration of the crystals from the solvent.
5. Washing the crystals with a cold solvent.
6. Collection and drying of the purified crystals.

This sequence defines the step-by-step process of purifying a solid using recrystallization. Initially, one must pick a suitable solvent where the solute's solubility increases with temperature. After dissolving the solid, the solution is cooled which prompts recrystallization since the solubility decreases as the temperature lowers, causing the purified substance to form crystals while impurities remain dissolved. Filtration separates the crystals, which are then washed to remove any solvent or remaining impurities, before drying to obtain the pure solid.