Since in aromatic amines the lone pair undergoes delocalisation, aliphatic amines are more basic than aromatic amines.
Ph−NH2<R−NH2
In an aliphatic amine, due to the +I effect of −CH3 the order will be 3∘>2∘>1∘.
In an aqueous solution, H−bonding takes place. So, the order will be 1∘>2∘>3∘.
However, the resultant basic order is due to a mixture of both the effects(+I and hydrogen bond). So, the order is 2∘>3∘>1∘.
So, the final basic order is
