Water/methanol and water/acetone are viable solvent systems for recrystallization,but water/chloroform

and water/pentane are not. Briefly explain in 1-2 sentences.

water/chloroform are not miscible.

Did you mean pentanol. Water/pentane is liquid/gas.

no its pentane

Frankly I don't see how a liquid/gas mixture would be of help in recrystallization of a solid.

Pentane boils at 35C or so; therefore, I suppose it is a liquid at room T but it isn't miscible with H2O.

Water/methanol and water/acetone are viable solvent systems for recrystallization because they have similar polarities and miscibility with water, allowing for effective solubility and crystallization of compounds. On the other hand, water/chloroform and water/pentane are not suitable because they have significantly different polarities and low miscibility with water, making it difficult to dissolve and recrystallize compounds.