Question

9 multiple choice 1 point when recrystallizing naphthalene, why is it important to filter the hot solution while it is still hot? to remove any undissolved impurities to increase the solubility of naphthalene to prevent the formation of large crystals to speed up the crystallization process

Explanation:

• Option 1: In recrystallization, filtering the hot solution removes undissolved impurities. Naphthalene is soluble in hot solvent, so undissolved solids (impurities) are filtered out before cooling (when naphthalene would crystallize).
• Option 2: Solubility of naphthalene depends on temperature; filtering doesn't increase solubility.
• Option 3: Filtering hot solution isn't related to preventing large crystals (crystal size is controlled by cooling rate).
• Option 4: Filtering doesn't speed up crystallization; cooling does.

Answer:

A. To remove any undissolved impurities