Which term describes flammable liquids that mix readily with water such as ethanol?

• A. Nonpolar solvent
• B. Polar solvent
• C. Hydrophobic solvent
• D. Aqueous solvent

Answer: (B)

The key idea is solvent polarity and how it relates to mixing with water. Ethanol is polar because it has a hydroxyl (O–H) group, giving the molecule a significant dipole and the ability to form hydrogen bonds with water. This polarity makes ethanol miscible with water, so it blends in all proportions rather than separating. That’s what the term polar solvent describes: a liquid whose molecules are polar and that mixes readily with water.

Nonpolar solvents lack that polarity and don’t mix well with water, so they’re not described this way. Hydrophobic solvents are water-repelling, which isn’t true for ethanol. Aqueous solvent refers to a water-containing medium, not to the intrinsic polarity of the solvent itself, so it doesn’t capture the idea of a solvent like ethanol that mixes with water due to polarity.