`A overset( "reduction ") to B overset(CHCl_3 //KOH ) to C overset("reduction ") to `N - methyl aniline then A is

Options

A.
B.
C. `CH_3NH_2`
D.

Answer

To solve the question step by step, we need to analyze the transformations described and identify the compound A.

### Step 1: Identify the final product
The final product mentioned is N-methyl aniline. This indicates that we need to trace back the reactions to find the starting compound A.

### Step 2: Understand the reduction process
The question states that A is reduced to give B. Since B is not specified, we can infer that B is likely a primary amine because it is a common product of the reduction of nitro compounds.

### Step 3: Identify the intermediate C
Next, we see that B reacts with CHCl3 in the presence of KOH to give C. This reaction is known as the carbylamine reaction, which typically involves a primary amine reacting with chloroform and a strong base to form an isocyanide.

### Step 4: Determine the structure of C
Since C is formed from a primary amine and is an isocyanide, we can deduce that C must be phenyl isocyanide (or isocyanate), which is derived from phenylamine (aniline).

### Step 5: Trace back to find A
To produce phenyl isocyanide, we need to start with a primary amine. The only way to obtain a primary amine from a compound is through the reduction of a nitro group. Therefore, A must be nitrobenzene, which upon reduction gives aniline (B), and then the carbylamine reaction with aniline gives phenyl isocyanide (C).

### Step 6: Confirm the final reduction
Finally, when phenyl isocyanide undergoes reduction, it yields N-methyl aniline, confirming that our initial assumption about A being nitrobenzene is correct.

### Conclusion
Thus, the compound A is **nitrobenzene**.

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