Give the IUPAC name of
(i) `CH_(3)-CH_(2)-CH_(2)-underset(CH_(3))underset(|)(CH)-CH_(2)-CH_(3)` (ii) `CH_(3)-underset(CHO)underset(|)(CH)-CH_(2)-CHO`
(iii) `CH_(3)-CH_(2)-underset(COOH)underset(|)(CH)-CH-CH_(3)`

Explanation

(i) 3-methylhexane (ii) 2-methylbutanul (iii) 2-ethylbut-3-enoic acid