Which of the following statements about anomalous expansion of water are correct? i. There is contraction…

Analyze the question: We need to pick the correct statements about the anomalous expansion of water.

Concept: Most liquids expand when heated. Water behaves differently between 0°C and 4°C. When ice at 0°C melts and the water is warmed, the water contracts until it reaches 4°C. Above 4°C it expands normally. So:

• Water has its minimum volume at 4°C.
• Water has its maximum density at 4°C (about 1000 kg/m³).

Checking each statement:

• i. There is contraction between 0°C and 4°C. Correct. This is the anomalous behaviour.
• ii. There is expansion between 0°C and 100°C. Not correct as a statement of anomalous expansion. Water contracts from 0°C to 4°C and only expands from 4°C to 100°C, so it does not expand throughout the range.
• iii. The volume is minimum at 4°C. Correct. Water contracts until 4°C, then expands, so the volume is lowest at 4°C.
• iv. The volume is maximum at 4°C. Wrong. It is the density that is maximum at 4°C, not the volume.

So the correct statements are i and iii.

Answer: C. i and iii only

Tip: Remember "4°C = smallest volume, biggest density." Volume and density always move in opposite directions for a fixed mass. This is also why ice floats and why fish survive in frozen lakes: the densest water (4°C) sinks to the bottom, while the colder water stays above it.