If we heat water, it will contract till the temperature of -

The correct answer is 4°C.

Key Points

• Water exhibits a unique property known as anomalous expansion, where it contracts upon heating until 4°C and expands when heated above this temperature.
• At 4°C, water reaches its maximum density, approximately 1 g/cm³, and begins to expand further as the temperature increases.
• This phenomenon occurs due to hydrogen bonding, which causes water molecules to arrange themselves more compactly at lower temperatures.
• Between 0°C and 4°C, the structure of ice-like clusters in water breaks down, leading to contraction until maximum density is achieved.
• The anomalous behavior of water is crucial for aquatic life as it prevents water bodies from freezing completely during winters.

Additional Information

• Anomalous Expansion of Water:
  • Most substances expand on heating; however, water contracts as it is heated from 0°C to 4°C.
  • This anomaly is caused by the unique molecular structure of water and the presence of hydrogen bonds.
• Hydrogen Bonding:
  • Water molecules form hydrogen bonds due to the polarity of its H-O bonds.
  • These bonds create a structured arrangement, leading to unique thermal properties like anomalous expansion.
• Density and Temperature Relation:
  • At 4°C, water achieves its maximum density, making colder water rise to the surface during freezing.
  • This property ensures that ice forms at the surface, insulating water below and protecting aquatic life during winters.
• Applications:
  • Understanding water's anomalous expansion is vital in environmental studies, aquatic ecosystem management, and engineering.
  • It explains why pipes may burst in cold weather and how lakes and ponds behave during freezing temperatures.