Question

What is the triple point of a substance?

Options

• The point where solid and liquid coexist only

• The point where the boiling point equals the melting point

• Where all three phases coexist.

•  The point at which a substance becomes a gas permanently

Answer 1

Where all three phases coexist

Explanation:

The triple point is where all three phase curves (l–v, l–s, s–v) meet. It is the only condition under which solid, liquid, and vapour can all exist together simultaneously.