Which of the following statements (s) is/are incorrect?
I. Ammonia is a stronger base than ethylamine
II. Aniline is a stronger base than p- methoxyaniline.
III. Aniline must be acetylated before nitration with an acid mixture.
Select the option.

Options

A. Only II
B. Only II
C. Only III
D. I and III

Answer

To determine which of the statements is incorrect, let's analyze each statement one by one.

### Statement I: Ammonia is a stronger base than ethylamine.
- **Analysis**: Ethylamine (C2H5NH2) is an aliphatic amine, and it has an ethyl group that is electron-donating. This increases the electron density on the nitrogen atom, making ethylamine a stronger base than ammonia (NH3). Therefore, this statement is **incorrect**.

### Statement II: Aniline is a stronger base than p-methoxyaniline.
- **Analysis**: Aniline (C6H5NH2) has a phenyl group that is electron-withdrawing due to resonance, which decreases the basicity of the nitrogen. On the other hand, p-methoxyaniline (C6H4(OCH3)NH2) has a methoxy group (-OCH3) that is an electron-donating group. This increases the electron density on the nitrogen atom, making p-methoxyaniline a stronger base than aniline. Thus, this statement is **incorrect**.

### Statement III: Aniline must be acetylated before nitration with an acid mixture.
- **Analysis**: Aniline is a strong base and can react with electrophiles, such as nitronium ions (NO2+), in nitration reactions. However, if aniline is nitrated directly, it can lead to polysubstitution and side reactions. Acetylation of aniline converts it into acetanilide, which is less basic and can be nitrated more selectively. Therefore, this statement is **correct**.

### Conclusion:
- The incorrect statements are **I and II**.

### Final Answer:
The incorrect statements are I and II.

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