How many isomers are possible for `C_(4)H_(8)F_(2)` and give their IUPAC names:

Explanation

n-Butane can have two possible gendifluoro isomers:
`underset("1,1-Difluorobutane")(F_(2)CHCH_(2)CH_(2)CH_(3)) " "underset("2,2-Difluorobutane")(CH_(3)CF_(2)CH_(2)CH_(3))`
There are four isomers with two fluorine on different carbon atoms:
`underset("1,2-Difluorobutane")(FCH_(2)CHFCH_(2)CH_(3))" "underset("2,2-Difluorobutane")(CH_(3)CHFCHFCH_(3))`
`underset("1,3-Difluorobutane")(FCH_(2)CH_(2)CHFCH_(3)) " "underset(1,4-"Difluorobutane")(CH_(3)CHFCHFCH_(3))`
The isobutane can have three possible difluoro isomers:
`FCH_(2)-underset(CH_(3))underset(|)CF-CH_(3) F_(2)CH-underset(CH_(3))underset(|)CH-CH_(3) FCH_(2)-underset(CH_(3))underset(|)CH-CH_(2)F`
`underset("propane(vic)")(1,2-"Difluoro-2-methlyl") " "underset("propane(gem)")(1,1-"Difluoro-2-methyl")" "underset("propane")(1,3-"Difluoro-2-methyl")`