i) Write the 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) and ii) Eight isomers of `C_(4)H_(11)N` are :
a) `underset("Primary")underset("Butan-1-amine")(overset(4)(CH_(3))-overset(3)(CH_(2))-overset(2)(CH_(2))-overset(1)(CH_(2))-NH_(2))`
b) `underset("Primary")underset("2-methylpropan-1-amine")(overset(3)(CH_(3))-overset(CH_(3))overset(""^(2)|)(CH)-overset(1)(CH_(2))-NH_(2))`
c) `underset("Primary")underset("Butan-2-amine")(overset(4)(CH_(3))-overset(3)(CH_(2))-overset(1)overset(CH_(3))overset(""^(2)|)(CH)-NH_(2))`
d) `underset("Primary")underset("2-methylpropan-2-amine")(CH_(3)- underset(CH_(3))underset(""_(3)|) overset(1)overset(CH_(3))overset(|)(""^(2)C)-NH_(2))`
e) `underset("Secondary")underset("N-ethylethanamine")(C_(2)H_(5)-overset(C_(2)H_(5))overset(|)(N)-H)`
f) `underset("Secondary")underset("N-methylpropan-1-amine")(C_(3)H_(7)-overset(CH_(3))overset(|)(N)-H)`
g) `underset("Secondary")underset("N-methylpropan-2-amine")(CH_(3)-overset(CH_(3))overset(|)(CH)-NH-CH_(3))`
h) `underset("Tertiary")underset("N, N-dimethylethanamine")(CH_(3)-overset(C_(2)H_(5))overset(|)(N)-CH_(3))`
iii) Isomerism exhibited by different amines are :
a) Chain isomers : i.e., have different carbon chains (a) and (b), ( c) and (d).
b) Position isomers : i.e., functional group occupy different positions. (b) and ( c), (b) and (d), (a) and (d).
c) Metamers : i.e., different alkyl groups are attached to the same functional group, (e) and (f), (g) and (e).
d) Functional isomers : i.e., have different functional groups. All the three categories `(1^(@),2^(@)and3^(@))` of amines are the functional isomers of each other.