Conditions necessary for combustion

• A substance will not burn without one or more of these conditions. 
• Combustible substance: Fuel
• Air (to supply oxygen)
• Heat (to raise the temperature beyond the ignition temperature)

Ignition temperature:

• The lowest temperature at which a substance catches fire is called ignition temperature.
• A combustible substance cannot catch fire or burn as long as its temperature is lower than its ignition temperature.
• The substances which have very low ignition temperature and can easily catch fire with a flame are inflammable substances. E.g. petrol, alcohol, LPG (Liquified petroleum gas) etc.
• Wood has high ignition temperature, if it is heated a little it will not catch fire.

Burning of match stick:

• The head of the safety match is made from antimony trisulphide and potassium chlorate. The rubbing surface has powdered glass and a little red phosphorous.
• When the matches is struck against the rubbing surface, some red phosphorous get converted into white phosphorous which reacts with the potassium chlorate in the match ignite antimony trisulphide and start the combustion.