(i) pKₕ of aniline is more than that of methylamine.

(ii) Ethylamine is soluble in water whereas aniline is not.

(iii) Methylamine in water reacts with ferric chloride to precipitate hydrated ferric oxide.

Let's break down the statements about aniline, methylamine, and ethylamine to understand their properties and behaviors.

Acidity Comparison

The first statement mentions that the pKₕ of aniline is greater than that of methylamine. This indicates that aniline is a weaker base compared to methylamine. The presence of the phenyl group in aniline stabilizes the positive charge on the nitrogen less effectively than the alkyl group in methylamine, making aniline less likely to accept protons.

Solubility in Water

Next, we look at solubility. Ethylamine is soluble in water, while aniline is not. Ethylamine has a smaller hydrophobic (water-repelling) alkyl group compared to aniline, which has a larger aromatic ring. This makes ethylamine more polar and better able to interact with water molecules, leading to its solubility.

Chemical Reactions with Ferric Chloride

The third point discusses methylamine's reaction with ferric chloride in water, resulting in the precipitation of hydrated ferric oxide. Methylamine can form complexes with ferric ions, leading to this precipitation. Aniline does not react in the same way due to its different structure and properties.

• Aniline: Weaker base, less soluble in water.
• Methylamine: Stronger base, reacts with ferric chloride.
• Ethylamine: Soluble in water, more polar.

In summary, these compounds exhibit distinct chemical behaviors based on their structures, affecting their acidity, solubility, and reactivity.