Question

pre-lab quiz 3. answer all questions 1 multiple choice 1 point which pair of solvents would not form an effective mixed solvent system for recrystallizing naphthalene? methanol-water hexane-methanol benzene-toluene ethanol-water next

Explanation:

To determine the ineffective mixed solvent system for recrystallizing naphthalene (a non - polar compound), we analyze the polarity of each solvent pair:

1. Methanol - water: Methanol is polar, water is polar. But their miscibility and ability to adjust polarity for non - polar naphthalene (by changing the ratio) make them a potential mixed solvent system.
2. Hexane - methanol: Hexane is non - polar, methanol is polar. They are immiscible (do not mix well), so they can't form a homogeneous mixed solvent system suitable for recrystallization.
3. Benzene - toluene: Both are non - polar aromatic solvents. They are miscible and can form a mixed solvent system for non - polar naphthalene.
4. Ethanol - water: Ethanol is polar, water is polar. Their miscibility and polarity adjustment (by ratio) make them a viable mixed solvent system.

Answer:

B. Hexane - methanol