Question

The point at which soild, liquid and gaseous forms of a substance co - exist is called

• A. sublimation
• B. distillation point
• C. triple point
• D. melting point

Answer 1

The Correct Option is C

The correct answer is triple point.

The concept of triple point refers to the unique set of conditions at which the three phases of a substance—solid, liquid, and gas—can coexist in thermodynamic equilibrium. This means that at the triple point, the temperature and pressure are precisely such that the substance can exist as a solid, liquid, and gas simultaneously.

This is a fundamental concept in thermodynamics and serves as a crucial fixed point in the definition of the Kelvin temperature scale. Each substance has its own specific triple point, characterized by distinct values of temperature and pressure.

The triple point is different from other points such as:

• Sublimation: The process where a substance transitions directly from a solid to a gas without passing through the liquid phase.
• Distillation point: A general term that refers to the boiling point under the conditions of distillation.
• Melting point: The temperature at which a solid becomes a liquid under normal atmospheric pressure.