Give the `IUPAC` names for the following:
(i) `CH_(3)underset(CH_(3))underset(|)(CH_(2))CHCO_(2)H`
(ii)
(iii)
(iv) `CH_(3)CH(CH_(3))CH(CH_(3))CH_(2)CO_(2)H`
Strategy: The `IUPAC` name of saturated aliphatic monocarboxylic acids is alkanoic acid. The carboxyl carbon atom is always numbered one while other substituents and side-chains get the lowest possible numbers. To avoid any mistake, it is always advised to open up the structure so that every possible substituent and side-chain is counted.

Explanation

(i) `2`-Methylbutanoic acid
(ii) `3`-Phenylpropanoic acid
(iii) `3`-(`p`-Chlorophenyl) butanoic acid
(iv) `3,4`-Dimethylpentanoic acid