do functional groups only act with alkanes. give scientific reasons

We can also include alkene, alkynes in the category of functional group. Functional grop can act with alkene and alkynes also.

The simplest hydrocarbon chain is alkane, when double bond attaches to it, it becomes alkene and if triple bond is attached to it, it becomes alkynes.

However, in alkene or alkyne chain, another functional group may get attached.

For example

CH₂=CH-CH₂-OH

Whose IUPAC name is Prop-3-en-1-ol

or

CH≡C-CH₂OH

Whose IUPAC is Prop-3-yn-1-ol