Which of the following statement is correct ?

Question

Accepted Answer

Option 3 is correct: "The density of ice is less than that of water."

Explanation for Option 3:
Ice is the solid form of water, and it has a unique property where its density is less than that of liquid water. This is due to the molecular structure of ice. In ice, water molecules form a crystalline structure maintained by hydrogen bonds, which creates an open hexagonal lattice. This structure causes the molecules to be spaced further apart than in liquid water, resulting in a lower density. This is why ice floats on water.

Explanation for why the other options are incorrect:

1. Option 1: "Material existing as liquids at room temperature have their melting and boiling points lower than that of room temperature."
   - This statement is incorrect because for a substance to exist as a liquid at room temperature, its melting point must be below room temperature, but its boiling point must be above room temperature. For example, water has a melting point of 0°C and a boiling point of 100°C, both of which are above and below room temperature, respectively.

2. Option 2: "To convert a temperature on Celsius scale to Kelvin scale, subtract 273 from the given temperature."
   - This statement is incorrect because the correct conversion from Celsius to Kelvin is to add 273.15 to the Celsius temperature, not subtract. The Kelvin scale is an absolute temperature scale, and 0 K is absolute zero, which is -273.15°C.

4. Option 4: "The process involving the transition of a substance from solid to liquid is called sublimation."
   - This statement is incorrect because the transition from solid to liquid is called melting, not sublimation. Sublimation is the process where a substance transitions directly from a solid to a gas without passing through the liquid phase, such as dry ice (solid carbon dioxide) turning into gas.