What do you understand by ‘triple point’ of a substance?

Explanation

### Step-by-Step Text Solution

1. **Definition of Triple Point**: The triple point of a substance is defined as the specific temperature and pressure at which the substance can coexist in all three states of matter: solid, liquid, and gas.

2. **Existence in All States**: At the triple point, the substance is in equilibrium between its solid, liquid, and gaseous states. This means that the rates of transition between these states (melting, freezing, evaporating, and condensing) are equal.

3. **Example of Water**: A well-known example is the triple point of water, which occurs at a temperature of 0.01 degrees Celsius and a specific pressure (approximately 611.657 pascals). At this point, water can exist simultaneously as ice (solid), liquid water, and water vapor (gas).

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