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.

Explanation

Compounds of hydrogen and carbon
Alkanes -`C_(n)H_(2n+2)`
Alkenes -`C_(n)H_(2n)`
Alkynes - `C_(n)H_(2n-2)`

Detailed Answer :
Certain compounds are called as hydrocarbond because they are formed mainly from carbon and hydrogen.
Formula for Homologous series of alkanes ,alkenes and alkynes :

Hydrogenation converts alkenes into alkane.
`CH_(2)=CH_(2)+H_(2)overset(PtPd//Ni)toCH_(3)-CH_(3)`
Dihydrogen gas adds to alkanes in the presence of finely divided catalysts like platinum , palladium or nickel to form alkanes.