Which from following amines has highest $\mathrm{pK}_{\mathrm{b}}$ value?
Which from following amines has highest $\mathrm{pK}_{\mathrm{b}}$ value?
Arylamine
Tertiary alkanamine
Secondary alkanamine
Primary alkanamine
Solution
In general, arylamines are weaker bases than aliphatic amines.
Hence, arylamine is the weakest base and its $\mathrm{pK}_{\mathrm{b}}$ value is the highest among the given aliphatic amines.