Ice is lighter than pure water and floats on the surface. Which one of the following statements is correct to explain this phenomenon ?

Ice floats on water because it is less dense than its liquid form. This density anomaly is primarily due to the unique hydrogen-bonding network in water. In the liquid state, water molecules are closely packed and constantly shifting. However, as water freezes into ice, the molecules arrange themselves into a highly ordered, crystalline lattice structure [t1][t3]. This structure is held together by hydrogen bonds that fix the molecules in a hexagonal pattern, creating an 'open' type structure with significant interstitial holes or empty spaces [t1][t3]. These holes increase the overall volume of the substance while the mass remains constant, thereby reducing its density compared to liquid water [t1]. Consequently, ice becomes approximately 9% less dense than liquid water, allowing it to float on the surface [c1]. Statements suggesting a disordered structure or a lack of hydrogen bonding in water are scientifically incorrect.

Sources

1. [1] Environment and Ecology, Majid Hussain (Access publishing 3rd ed.) > Chapter 12: Major Crops and Cropping Patterns in India > Biotic: Living > p. 113