Which method is commonly used for purifying organic solids?

Which method is commonly used for purifying organic solids?

• A. Filtration
• B. Vacuum distillation
• C. Recrystallization
• D. Extraction

Answer: (C)

Recrystallization is the commonly used method for purifying organic solids due to its effectiveness in separating impurities based on their differing solubility. In this technique, a solid is dissolved in a hot solvent to create a saturated solution, and then the solution is allowed to cool slowly. As it cools, the solubility of the original compound decreases, leading to the crystallization of the pure compound while most impurities remain dissolved in the solvent. This process can be repeated to increase purity, as slight adjustments to solvent choice and temperature can optimize the yield and quality of the resulting crystals. Recrystallization is particularly beneficial when dealing with compounds that have distinct solubility properties, allowing for effective separation and purification. While filtration can be used to separate solid from liquid, it does not enhance purity through solubility differences. Vacuum distillation is more suitable for separating liquids with different boiling points rather than purifying solids. Extraction is effective for separating components based on their solubility in different solvents but is not specifically tailored for solid-phase purification as recrystallization is.

Recrystallization is the commonly used method for purifying organic solids due to its effectiveness in separating impurities based on their differing solubility. In this technique, a solid is dissolved in a hot solvent to create a saturated solution, and then the solution is allowed to cool slowly. As it cools, the solubility of the original compound decreases, leading to the crystallization of the pure compound while most impurities remain dissolved in the solvent.

This process can be repeated to increase purity, as slight adjustments to solvent choice and temperature can optimize the yield and quality of the resulting crystals. Recrystallization is particularly beneficial when dealing with compounds that have distinct solubility properties, allowing for effective separation and purification.

While filtration can be used to separate solid from liquid, it does not enhance purity through solubility differences. Vacuum distillation is more suitable for separating liquids with different boiling points rather than purifying solids. Extraction is effective for separating components based on their solubility in different solvents but is not specifically tailored for solid-phase purification as recrystallization is.