Q. why dose carbon form a huge number of its compounds ? 

due to tetravalency

and catenation

carbon can form huge number of its compounds because its valency is 4 so it can either lose four electrons or gain four electrons i.e tetra valency

Carbon is an element which shows the oxidation state of 4 which combined with its property of catenation, makes it possible to form a huge number of compounds. Catenation is the property by which it can make bonds with other carbon atoms to form long chains.