Methane is the simplest hydrocarbon and is the first member of homologous series of alkanes. Some of the sources of methane are:- Methane us the major constituent of gobar gas and sewage gas obtained by decomposition of animal dung, excreta and plant wastes. Methane gas is also produced by bacteria living the gut (digestive track) of cattle and termites.
Methane like carbon dioxide, also traps infrared radiations (heat radiations) reflected by the earth. As a result, methane gas also contributes to the greenhouse effect. Actually, a molecule of methane traps twenty times more heat radiations than a carbon dioxide molecule.
Methane burns in excess of air or oxygen with a pale-blue nonluminous flame to give carbon dioxide and water. The combustion reaction is highly exothermic. Therefore, methane is an excellent fuel.
As a fuel for domestic and industrial purpose because it produces large amount of heat and leaves no ash on burning. For the manufacture of carbon black. Carbon black is used for making paints, black printing ink etc.
Formation of methane (CH4) molecule on the basis of electronic theory of valence is described below. The electronic configuration of carbon is K, L: 2, 4. Thus, there are four electrons in the valence shell of carbon atom. To complete its octet, it needs four more electrons.
In a methane molecule, four hydrogen atoms are linked to one carbon atom by single covalent bonds. The four valence bonds of carbon are arranged tetrahedrally in space. Thus , a methane molecule has been a tetrahedral shape.