Which of the following liquids is least viscous? Assume temperature is 25°C.

The answer is acetone because it has a relatively low viscosity compared to the other liquids mentioned. Viscosity is a measure of a liquid's resistance to flow, with low viscosity indicating a fluid that flows easily. Acetone is a volatile and highly flammable liquid commonly used as a solvent. Its low viscosity and ability to quickly evaporate make it less viscous than honey, cooking oil, and glycerin. The molecular structure and intermolecular forces of acetone contribute to its lower viscosity, allowing it to flow more freely.