Write down the IUPAC names of the alkyl groups having the molecular formula , `C_(4)H_(9)`.

Explanation

Four alkyl groups are possible. These are -
(i) `underset("butyl)(-CH_(2)CH_(2)CH_(3))`
(ii) `-underset(CH_(3)("sec-butyl"))underset(|)(CH)-CH_(2)CH_(3)`
(iii) `-CH_(2)-underset(CH_(3)("isobutyl"))underset(|)(CH)-CH_(3)`
(iv) `underset("tert-butyl)(-C(CH_(3))_(3))`