Method by which aniline cannot be prepared is:

Options

A. hydrolysis phenyl isocyanide with acidic solution
B. degradation of benzamide with bromine in alkaline solution
C. reduction of nitrobenzene with `H_(2)//Pd` in ethanol
D. potassium salt of phthalimide treated with chlorobenzene followed by the hydrolysis with aqueous NaOH solution

Explanation

To determine the method by which aniline cannot be prepared, we will analyze various methods of synthesis and identify the one that does not yield aniline.

### Step-by-Step Solution:

1. **Hydrolysis of Phenyl Isocyanide:**
- Phenyl isocyanide (C6H5N=C=O) undergoes hydrolysis in an acidic solution.
- The reaction produces N-phenylformamide (C6H5NHCHO).
- Further hydrolysis of N-phenylformamide yields aniline (C6H5NH2).
- **Conclusion:** This method can produce aniline.

2. **Degradation of Benzamide with Bromine and Alkaline Solution:**
- Benzamide (C6H5CONH2) reacts with bromine (Br2) in the presence of an alkaline solution (NaOH).
- The reaction results in the formation of aniline along with by-products (Na2CO3, NaBr, and water).
- **Conclusion:** This method can also produce aniline.

3. **Reduction of Nitrobenzene:**
- Nitrobenzene (C6H5NO2) is reduced using hydrogen (H2) in the presence of palladium (Pd) in ethanol.
- This reduction yields aniline (C6H5NH2) and water.
- **Conclusion:** This method can produce aniline.

4. **Reaction of Potassium Salt of Thalimide with Alkyl Halide:**
- The potassium salt of thalimide reacts with an alkyl halide (R-X).
- This reaction forms N-alkyl thalimide.
- When treated with aqueous NaOH, it produces RNH2 and the sodium salt of thalimide.
- However, if R is a phenyl group (C6H5), the reaction does not yield aniline due to the nature of aryl halides, which favor electrophilic substitution rather than nucleophilic substitution.
- **Conclusion:** This method cannot produce aniline when starting with an aryl halide.

### Final Answer:
The method by which aniline cannot be prepared is the reaction of the potassium salt of thalimide with an aryl halide.

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