Question

water and alcohol are two liquids that mix completely but can be separated by distillation. what property allows this separation?
density color
boiling point melting point

Explanation:

Distillation separates mixtures by heating to vaporize a component and then condensing it. Water (boiling point ~100°C) and alcohol (e.g., ethanol ~78.4°C) have different boiling points. Density relates to mass/volume, color is visual, and melting point is for solids turning liquid—none relate to distillation of liquids. So boiling point is the property.

Answer:

boiling point