At which temperature does liquid water show maximum density ?

Liquid water exhibits a unique physical property known as the anomalous expansion of water. While most substances increase in density as they cool and contract, water reaches its maximum density at approximately 4°C.

• To convert temperature from Celsius to Kelvin, the standard formula is: K = °C + 273.15.
• Substituting the value: 4°C + 273.15 ≈ 277.15 K.

Therefore, 277 K (Option B) is the correct temperature. As water cools from 4°C down to 0°C, it actually begins to expand and its density decreases. This happens because hydrogen bonds start forming a structured, open hexagonal lattice, which takes up more space. This unique behavior is why ice floats on water and why aquatic life can survive in frozen lakes, as the densest water (4°C) remains at the bottom.