Normal boiling point

The boiling point of a substance is the temperature at which the vapor pressure of the liquid equals the atmospheric pressure. At this temperature, bubbles of vapor form within the liquid and rise to the surface, causing the liquid to boil.

Definition
The normal boiling point is the boiling point of a substance at a pressure of 1 atmosphere (atm), which is equivalent to 101.3 kilopascals (kPa) or 760 millimeters of mercury (mmHg). It is a standard reference point used for comparing the boiling points of different substances.

Explanation
- The boiling point of a liquid is dependent on the surrounding pressure. As the pressure increases, the boiling point of the liquid also increases.
- Conversely, as the pressure decreases, the boiling point of the liquid decreases.
- The normal boiling point is specifically defined at a pressure of 1 atm, allowing for consistent comparison between different substances under standard conditions.
- It provides a reference point for scientists and engineers to communicate and compare the boiling points of different substances.
- The normal boiling point is often used in laboratory experiments, industrial processes, and everyday applications to determine the appropriate temperature at which a substance will boil.
- It is important to note that the normal boiling point may vary slightly depending on the altitude or location, as atmospheric pressure can vary with elevation.
- However, for most practical purposes, the normal boiling point is considered to be constant at 1 atm.

In summary, the normal boiling point refers to the temperature at which a substance boils when the pressure is 1 atm. It is a standard reference point used to compare the boiling points of different substances under consistent conditions.