Answer :
Water is considered a special molecule due to its unique properties that distinguish it from other substances. Here's why it is so unusual:
1. Water is a liquid at room temperature, unlike other molecules of similar size, which are often gases at room temperature. This is significant because water's liquid form allows for various biological processes to occur within living organisms.
2. Water has the ability to dissolve many polar and ionic compounds. This property is crucial for life as it enables water to serve as a universal solvent, facilitating chemical reactions in biological systems.
3. Water exhibits all of the above characteristics listed in the options. These properties collectively make water a versatile and essential substance for life on Earth.
4. Water has a high boiling point compared to molecules of similar size. This elevated boiling point is attributed to the strong hydrogen bonds between water molecules, which require more energy to break and transition water from a liquid to a gaseous state.
5. When water freezes, it expands instead of contracting like most substances. This unique behavior is due to the formation of a hexagonal lattice structure during freezing, causing water to be less dense in its solid form compared to its liquid form. This property of water is why ice floats on water.
In summary, water's unusual properties, such as being a liquid at room temperature, its solvent capabilities, high boiling point, and expansion upon freezing, make it a remarkable and vital molecule for various biological and chemical processes.
