The correct order of increasing basic nature forthe bases \( \mathrm{NH}_{3}, \mathrm{CH}_{3} \mathrm{NH}_{2} \) and \( \left(\mathrm{CH}_{3}\right)_{2} \mathrm{NH} \)
inaqueous solutions

The basic nature of aliphatic amines should increase with increase in number of alkyl groups as the alkyl groups are \( e^{-} \)
releasing groups ( \( +1 \) inductive effect) and it will increase the \( e^{-} \)density on \( N \), therefore, its basicity should increase, but
in aqueous solutions it has been observed that tertiary amines are unexpectedly less basic then the others due to steric
hindrance by the alkyl groups. Therefore, the correct order of increasing basic nature for the bases is;
\( \left(\mathrm{CH}_{3}\right)_{2} \mathrm{NH}>\mathrm{C}_{3} \mathrm{NH}_{2}>\left(\mathrm{CH}_{3}\right)_{3} \mathrm{~N}> \) ammonia.