Which of the following statement/s is/are wrong?

A. Methyamine is more basic than ammonia.

B. Amines form hydrogen bond.

C. Ethylamine has higher boiling point than propane.

D. Dimethylamine is less basic than methylamine.

E. Amines are soluble in organic solvents like alcohol.

Choose the correct answer from the options given below:

D only

The correct answer is option 2. D only.

Let us go through each statement in detail to understand why certain statements are correct and why others are incorrect.

Statement A: Methylamine is more basic than ammonia.

Basicity in amines is determined by the availability of the lone pair of electrons on the nitrogen atom to accept a proton (H\(^+\)). In methylamine \((\text{CH}_3\text{NH}_2)\), the methyl group (\(\text{CH}_3\)) is an electron-donating group through its +I effect (inductive effect). This increases the electron density on the nitrogen atom, making the lone pair more available for protonation. In ammonia \((\text{NH}_3)\), there are no alkyl groups, so the nitrogen has a lower electron density compared to methylamine. Therefore, methylamine is more basic than ammonia because the lone pair on nitrogen in methylamine is more readily available to accept a proton.

Conclusion: This statement is correct.

Statement B: Amines form hydrogen bonds.

Hydrogen bonding occurs when hydrogen is attached to a highly electronegative atom (like nitrogen, oxygen, or fluorine) and can interact with the lone pair of electrons on another electronegative atom. Primary (RNH\(_2\)) and secondary (R\(_2\)NH) amines can form hydrogen bonds because they have N-H bonds. The hydrogen atoms attached to nitrogen can form hydrogen bonds with electronegative atoms in other molecules. Tertiary amines (R\(_3\)N) cannot form hydrogen bonds as donors since they lack N-H bonds, but they can still accept hydrogen bonds due to the lone pair on nitrogen.

Conclusion: This statement is correct.

Statement C: Ethylamine has a higher boiling point than methylamine.

The boiling point of a compound is influenced by the strength of intermolecular forces, particularly hydrogen bonding and van der Waals forces. Ethylamine \((\text{C}_2\text{H}_5\text{NH}_2)\) is a larger molecule than methylamine \((\text{CH}_3\text{NH}_2)\), and it has more surface area. This results in stronger van der Waals forces between ethylamine molecules. Both ethylamine and methylamine can form hydrogen bonds, but the larger size of ethylamine gives it a higher boiling point.

Conclusion: This statement is correct.

Statement D: Dimethylamine is less basic than methylamine.

Dimethylamine \((\text{(CH}_3)_2\text{NH})\) has two methyl groups attached to the nitrogen atom. Each methyl group donates electron density to the nitrogen through the +I effect, increasing the electron density on nitrogen. Methylamine \((\text{CH}_3\text{NH}_2)\) has only one methyl group, so the electron density on the nitrogen is less compared to dimethylamine. Higher electron density on the nitrogen in dimethylamine means the lone pair is more available for protonation, making dimethylamine more basic than methylamine.

Conclusion: This statement is incorrect.

Statement E: Amines are soluble in organic solvents like alcohol.

Amines are generally soluble in organic solvents such as alcohol because they can form hydrogen bonds with the alcohol molecules. The solubility of amines in organic solvents is due to their ability to engage in hydrogen bonding and their compatibility with the polar and non-polar regions of organic molecules. This solubility makes amines versatile in both polar and non-polar organic solvents.

Conclusion: This statement is correct.

Thus, the incorrect statement is D.