Ethylamine is soluble in water whereas aniline is almost insoluble. Why?

Explanation

Ethylamine `(C_(2)H_(5)NH_(2))` is soluble in water because `-NH_(2)` group forms hydrogen bond with water molecule efficiently due to increased electron density on N atom because of (+I) inductive effect of `-C_(2)H_(5)` group. Also, the hydrocarbon part, `-C_(2)H_(5)` is small and do not contribute much towards hydrophobicity.
In Aniline `(C_(6)H_(5)NH_(2))` the `-NH_(2)` group is involved in resonance with the benzene ring with which it is directly attached, hence it does not make efficient hydrogen bonds with water. Secondly, the benzene ring is bulky and hydrophobic to a great extent. Hence, the overall effect is insolubility of aniline in water.