(i) Write structures of different isomeric amines corresponding to the molecular formula, `C_(4)H_(11)N.`
ii) Write IUPAC names of all the isomers.
(iii) What type of isomerism is exhibited by different pairs of amines?

Explanation

(i), (ii)
Primary amines
(a) `underset("Butanamine")(CH_(3)CH_(2)CH_(2)CH_(2)NH_(2))` (b) `underset("Butan-2-amine")(CH_(3)CH_(2)-underset(NH_(2))underset(|)CH-CH_(3))` (c) `underset("2-Methylpropanamine")(overset(3)(CH_(3))underset(CH_(3))underset(|)overset(2)(CH)-overset(1)(CH_(2))-NH_(2))` (d) `underset("propan-2-amine")underset("2-Methyl")(CH_(3)-underset(CH_(3))underset(|)overset(CH_(3))overset(|)(C)—NH_(2))`
Secondary amines (e) `underset("N-methylpropanamine")(CH_(3)CH_(2)CH_(2)NHCH_(3))` (f) `underset("N-Methylpropan-2-amine")(CH_(3)underset(CH_(3))underset(|)CH–NH–CH_(3))` (g) `underset("N-Ethylethanamine")(CH_(3)CH_(2)–NH–CH_(2)CH_(3))`
Tertiary amines
(h) `underset("N, N-Dimethylethanamine")(CH_(3)-underset(CH_(3))underset(|)NCH_(2)CH_(3))`
(iii) (a) - (b) and (e) - (f) are position isomers.
(a) - (c), (b) – (d) and (a) - (d) are chain isomers.
(e) - (g) and (f) and (g) are metamers.