(a) What are hydrocarbons ? Give examples.
(b) Give the structural differences between saturated and unsaturated hydrocarbons with two examples each.
(c ) What is functional group ? Examples of four different functional groups.

Explanation

(a) Hydrocarbons are the organic compounds containing only carbon and hydrogen atoms as their constituents. These may be alkanes, alkenes and akynes.
(b) Saturated hydrocarbons or alkanes contains either C-C and C-H bonds in their molecules. These are represented by the general formula `C_(n)H_(2n+2)`. for example.
`underset("Ethane")(H-underset(H)underset(|)overset(H)overset(|)(C)-underset(H)underset(|)overset(H)overset(|)(C)-H)" "underset("Propane")(H-underset(H)underset(|)overset(H)overset(|)(C)-underset(H)underset(|)overset(H)overset(|)(C)-underset(H)underset(|)overset(H)overset(|)(C)-H)`
Unsaturated hydrocarbons contain either atleast one `gtC=Clt` bond or triple `-C-=C-` bond in their molecules. these may be either alkenes or alkynes in nature. the general formula of alkenes is `C_(n)H_(2n)` while that of alkynes is `C_(n)H_(2n-2)`. for example.
`underset("Ethene")(H-overset(H)overset(|)(C)-=overset(H)overset(|)(C)-H)" "underset("Propene")(H-underset(H)underset(|)overset(H)overset(|)(C)-underset(H)underset(|)(C)=underset(H)underset(|)(C)-H)" "underset("Ethyne")(H-C-=C-H)" "underset("Propyne")(H-underset(H)underset(|)overset(H)overset(|)(C)-C-=C-H)`
(c) For the definition of functional group and example.