Can you guess what is common in
rusting or iron, burning coal and the flame of candle? They all undergo a
chemical reaction known as combustion. Combustion is a
chemical reaction that occurs in the presence of a fuel and an oxidizing agent
that produces energy, usually in the form of heat and light.
What we call as ‘burning’ is really
a combustion reaction. In fact combustion is one of the first chemical
reactions intentionally harnessed by humans. Any reaction that involves
reaction with oxygen is called oxidation reaction. In the combustion of
hydrocarbon with oxygen, typically carbon dioxide and water are produced.
(Hydrocarbon) + (Oxygen) →
(Carbon dioxide) (Water)
All combustion reactions are
exothermic; that is they release heat.
The minimum temperature at which a
substance catches fire and burns is called its ignition temperature.
A substance will not catch fire and
burn if its temperature is lower than its ignition temperature. Different
substances have different ignition temperatures.
Substances which have very low ignition
temperature and can easily catch fire with a flame are called inflammable
substances. E.g. Petrol. Alcohol, LPG (Liquefied Petroleum Gas), CNG
(Compressed Natural Gas), etc.