What is the Difference Between Flash Point and Boiling Point?

The main difference between flash point and boiling point lies in their temperatures and the conditions under which they occur:

• Flash Point: This is the lowest temperature at which the vapor of a substance can ignite in air when exposed to an ignition source. Flash point is specific to volatile liquids and is the lowest temperature at which the vapor pressure of the liquid is sufficient to support combustion. The flash point depends on the boiling point and subsequent vapor pressure of the liquid.
• Boiling Point: This is the temperature at which the vapor pressure of a liquid equals the external pressure, causing the liquid to change into a vapor. Boiling point is applicable to any liquid and occurs when the thermal energy of the liquid is enough to break the intermolecular bonds. When a liquid reaches its boiling point, bubbles form inside the liquid, rather than above it.

In summary, the flash point is the temperature at which a liquid's vapor can ignite, while the boiling point is the temperature at which the liquid turns into a vapor. Every liquid has a boiling point, but only volatile liquids have a flash point.

Comparative Table: Flash Point vs Boiling Point

The key difference between flash point and boiling point is that every liquid has a boiling point, but only volatile liquids have a flash point. Here is a table summarizing the differences between flash point and boiling point:

In summary, the flash point is the lowest temperature at which a volatile liquid's vapor ignites when exposed to an ignition source, while the boiling point is the temperature at which a liquid turns into a gas, and its vapor pressure equals the external pressure.