The temperature or point at which the vapor pressure of a liquid equals the external pressure applied.

The temperature or point at which the vapor pressure of a liquid equals the external pressure applied.

• A. Boiling Point
• B. Melting Point
• C. Flash Point
• D. Sublimation Point

Answer: (A)

Boiling point is the temperature at which a liquid’s vapor pressure equals the surrounding pressure. At that point, bubbles of vapor form within the liquid and rise to the surface, producing vigorous evaporation into gas. This temperature shifts with external pressure: lowering the pressure lowers the boiling point, while increasing the pressure raises it. For example, water boils at 100°C at one atmosphere of pressure. The other terms describe different phenomena: melting point is the temperature at which a solid becomes a liquid; flash point is the lowest temperature at which vapors can ignite in the presence of an ignition source; sublimation point is the temperature at which a solid turns directly into a gas without becoming liquid.

Boiling point is the temperature at which a liquid’s vapor pressure equals the surrounding pressure. At that point, bubbles of vapor form within the liquid and rise to the surface, producing vigorous evaporation into gas. This temperature shifts with external pressure: lowering the pressure lowers the boiling point, while increasing the pressure raises it. For example, water boils at 100°C at one atmosphere of pressure.

The other terms describe different phenomena: melting point is the temperature at which a solid becomes a liquid; flash point is the lowest temperature at which vapors can ignite in the presence of an ignition source; sublimation point is the temperature at which a solid turns directly into a gas without becoming liquid.