Alkane, alkene, alkyne- chemical reaction

Why are certain compounds called hydrocarbons? Write the general formula for homologous series of alkenes and alkynes and also draw the structure of the first member of each series. Write the name of the reaction that converts alkenes into alkanes and also write a chemical equation to show the necessary conditions for the reaction to occur.

Examples of alkanes|alkenes|alkynes| functional group|alkyl acetate

(a) Give the general formula of an : (i) alkane,(ii) alkene,(iii) alkyne. (b) Classify the following compounds as alkanes , alkanes and alkynes: C_(2)H_(4),C_(3)H_(4),C_(4)H_(8),C_(5)H_(12),C_(3)H_(8),C_(6)H_(6)