Which of the following liquids is the least dense?

• A. Water
• B. Mercury
• C. Ethanol
• D. Glycerol

Answer: (C)

Verified step by step guidance

1. Recall that density is defined as mass per unit volume, given by the formula \(\text{density} = \frac{\text{mass}}{\text{volume}}\).
2. Understand that the density of a liquid depends on how closely packed its molecules are and the mass of those molecules.
3. Consider the typical densities of the given liquids: water, mercury, ethanol, and glycerol. Mercury is a metal in liquid form and is known to be very dense, much denser than water.
4. Ethanol is an organic alcohol with relatively light molecules and less tightly packed structure compared to water and glycerol, so it generally has a lower density.
5. Glycerol is a viscous liquid with a higher molecular weight and stronger intermolecular forces than ethanol, making it denser than ethanol but less dense than mercury.