Question

Why does recrystallization of a compound usually result in its purification?

A. The growing crystal lattice self-selects for that compound's molecules; impurities remain behind in the solution and are removed by filtration.

B. Crystalline compounds are more pure than amorphic compounds by definition.

C. Mechanical agitation of the boiling mixture physically separates the solute from its impurities by friction.

D. Impurities are chemically destroyed by solvolysis.

Answer 1

Recrystallization technique is based on the principle that involves dissolution of the impure compound in the appropriate solvent and heat it. When it is heated then impurities and compound both are dissolved in the solvent. When this solution is allowed to cool then crystallization starts. While crystallization, the impurities are excluded and pure compound is crystallized.

So answer for this question is :

A. The growing crystal lattice self-selects for that compound's molecules; impurities remain behind in the solution and are removed by filtration.