`R-NH_2 ` is the main product of reaction of` RCONH_2 ` and `[Br_2+ KOH ].` In this reaction intermediates are :
`(a ) RCONHBr (b ) RNHBr `
`(c ) R-N=C=O " " (d ) RCONBr_2`
Correct answer is :

Options

A. a,b
B. a,c
C. c,d
D. b,c,d

Answer

To solve the problem, we need to analyze the reaction of RCONH2 (an amide) with Br2 and KOH. This reaction is known as the Hofmann degradation reaction. Let's break down the steps involved in this reaction and identify the intermediates.

### Step-by-Step Solution:

1. **Identify the Reaction**:
The reaction involves an amide (RCONH2) reacting with bromine (Br2) in the presence of a strong base (KOH).

2. **Formation of the First Intermediate**:
When RCONH2 reacts with Br2, the bromine will substitute one of the hydrogen atoms on the nitrogen atom, forming RCONHBr. This is the first intermediate.

**Intermediate A**: RCONHBr

3. **Deprotonation**:
The presence of KOH will lead to the deprotonation of the nitrogen atom in RCONHBr. The hydroxide ion (OH-) from KOH will abstract a proton (H+) from the nitrogen, resulting in RCON^- (the negatively charged amide) and Br-.

4. **Formation of the Second Intermediate**:
The negatively charged nitrogen will now be unstable and will eliminate the bromine atom (Br-) leading to the formation of RNHBr.

**Intermediate B**: RNHBr

5. **Formation of Nitrile**:
The nitrogen can rearrange to form a nitrile (R-N=C=O). This step involves the migration of the R group to the nitrogen, resulting in the formation of a compound with a double bond between nitrogen and carbon.

**Intermediate C**: R-N=C=O

6. **Hydrolysis**:
When water is added to the reaction mixture, the nitrile can undergo hydrolysis to form carbamic acid (RNHCOOH). This is an important step leading to the final product.

7. **Final Product Formation**:
Upon heating, carbamic acid will decompose to yield R-NH2 (the amine) and carbon dioxide (CO2).

### Conclusion:
The intermediates formed during the reaction of RCONH2 with Br2 and KOH are:
- A: RCONHBr
- C: R-N=C=O

Thus, the correct answer to the question is that the intermediates are (a) RCONHBr and (c) R-N=C=O.