Arrange the following amines in the decreasing order of their solubilities in water.

Step-by-step solution

The solubility of amines in water depends on their ability to form hydrogen bonds with water molecules. Amines with lower molecular weight and fewer hydrophobic alkyl groups are generally more soluble. Compound [I] is aniline ( C₆H₅NH₂ ), which contains a large hydrophobic phenyl group. This large hydrocarbon part significantly reduces its solubility in water. Compound [II] is ethylamine ( CH₃CH₂NH₂ ), a primary amine with a small alkyl group. It can form effective hydrogen bonds with water and has a smaller hydrop