Coal and petroleum are the fossils fuels. Carbon compounds undergo different types of chemical reactions. All carbon compounds react with oxygen to produce heat and light along with carbon dioxide and water. This reaction of carbon with oxygen is called combustion.
Carbon Compound + Oxygen
Aliphatic compounds on combustion produce a non-sooty flame. for example, alcohol burns with a blue flame and does not produce any soot. Aromatic compounds on combustion produce sooty flame. For example, naphthalene and camphor burn with a yellow flame and produce soot.
Alcohols undergo oxidation in presence of oxidising agents like alkaline potassium permanganate or acidified potassium dichromate to form carboxylic acids. For example, ethyl alcohol on oxidation with alkaline potassium permanganate or acidified potassium dichromate gives acetic acid.
Addition reaction is the one in which a molecule adds across a double bond or a triple bond.
Unsaturated hydrocarbons undergo addition reactions. Hydrogenation reaction involves the addition of hydrogen to unsaturated hydrocarbons in presence of catalyst like nickel to form saturated hydrocarbons.
A substitution reaction involves the replacement of an atom or group of atoms by other atom or group. Alkanes undergo substitution reactions. For example chlorination of methane in presence of sunlight gives a mixture of products like methyl chloride, methylene chloride, chloroform, and carbon tetrachloride.