Question

what is rapid combustion and spontaneous combustion?different between rapid and spontaneous combustion?

Answer 1

when the gas but rapidly with evolution of heat and light is rapid combustion
when a material bursts into flame is spontaneous combustion

Answer 2

Rapid combustion: When a combustible substance burns quickly, producing a large amount of heat and light us called a rapid combustion.

example: cooking gas etc.

Spontaneous combustion: In some cases as that of forest fires, the atmospheric temperature reaches to the extent that it exceeds the ignition temperature of the dry forest grass and this process of combustion is called spontaneous combustion.

example: grass catches the fire and this fire spreads to cause forest fires.