Question

Assertion :Water is denser than ice at same temperature. Reason: The maximum density of water occurs at a temperature of $4^{0}C$ and after this temperature water expands on cooling.

• A. Both Assertion and Reason are correct and Reason is the correct explanation for Assertion
• B. Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion
• C. Assertion is correct but Reason is incorrect
• D. Both Assertion and Reason are incorrect

Answer 1

The correct option is B Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion

An unusual property of ice frozen at atmospheric pressure is that the solid is approximately $8.3\%$ less dense than liquid water. The density of ice is $0.9167g/c{m}^3$ at $0°C$, whereas water has a density of $0.9998g/c{m}^3$ at the same temperature. Liquid water is densest, essentially $1.00g/c{m}^3$, at $4°C$ and becomes less dense as the water molecules begin to form the hexagonal crystals of ice as the freezing point is reached. This is due to hydrogen bonding dominating the intermolecular forces, which results in a packing of molecules less compact in the solid. Density of ice increases slightly with decreasing temperature and has a value of $0.9340g/c{m}^3$ at $-180°C\left(93K\right)$.