What is the Difference between flash point and boiling point?

Answer 1

oiling Point

Boiling point is a property of a liquid. The boiling point is defined as the temperature, where the vapor pressure of the liquid is equal to the external pressure on the liquid. Ideally, a liquid placed at a vacuum space would be at its melting point on zero kelvins (absolute zero). Higher the external pressure higher would be the melting point. This is the simple theory behind pressure cookers. A pressure cooker is a device, where the vapor from the heated water is trapped inside the container. The high amount of vapor inside the container makes external pressure on the liquid higher. This high pressure results a higher boiling point. This method is very useful especially on higher altitudes. Since the atmospheric pressure is lower on higher altitudes, water will boil between 80 0C - 90 0C. This will cause undercooked meals. A liquid boils when it exceeds its saturation temperature at the corresponding saturation pressure. Saturation temperature is defined as the temperature corresponding to the highest thermal energy the liquid can hold without changing its state to vapor at the given pressure. The saturation temperature is also equivalent to the boiling point of the liquid. Boiling occurs when the thermal energy of the liquid is enough to break the intermolecular bonds. The normal boiling point is defined as the saturation temperature at atmospheric pressure. The boiling point varies only between the triple point and the critical point of the liquid.

Answer 2

Autoignition temperature is the temperature above which adequate energy is available to provide an ignition source. For instance a hydrocarbon vapor released to the earth's atmosphere at or above its autoignition temperature will spontaneously combust (no other ignition sources are needed).

Flash point is the lowest temperature of a liquid, which still emits enough vapor to form an ignitable mixture with air. To find the flash point, the temperature of a liquid exposed to the atmosphere is slowly increased with a flame exposed to the resulting vapors. The temperature at which the first ignition occurs is the flash point.

Source: Chemical Process Safety: Fundamentals with Applications, 2nd ed. by Daniel A. Crowl and Joseph F. Louvar, p. 227

Answer 3

The flash point is the temperature at which a particular substance can form an ignitable mixture with air. Autoignition temperature is the temperature where it is certain that the compound in question will react.