`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 regarding the reaction of RCONH2 with Br2 and KOH, we will analyze the mechanism of the Hofmann Bromamide reaction step by step.

### Step 1: Understanding the Reactants
The reactant in this case is an amide, RCONH2. When it reacts with bromine (Br2) in the presence of a strong base like KOH, we need to identify the intermediates that form during this reaction.

**Hint:** Identify the functional groups present in the reactants and their reactivity.

### Step 2: Base Abstraction
In the first step of the reaction, the strong base (KOH) abstracts one of the acidic hydrogens from the amide. This results in the formation of a negatively charged nitrogen species, which can be represented as R-C(=O)-NH-.

**Hint:** Look for the acidic hydrogen in the amide that can be removed by the base.

### Step 3: Formation of Bromamide
The negatively charged nitrogen acts as a nucleophile and attacks the bromine molecule (Br2). This leads to the formation of an intermediate bromamide, R-C(=O)-NH-Br.

**Hint:** Consider how nucleophiles interact with electrophiles in organic reactions.

### Step 4: Further Base Abstraction
Another molecule of the base (KOH) abstracts the remaining acidic hydrogen from the bromamide intermediate. This results in the formation of R-C(=O)-Br, with the bromine now being part of the carbonyl compound.

**Hint:** Identify the role of the base in facilitating the removal of protons in the reaction.

### Step 5: Formation of Isocyanate
The bromine atom is released, leading to the formation of a nitrene intermediate. This nitrene can rearrange to form an isocyanate, R-N=C=O.

**Hint:** Understand the rearrangement processes that can occur with intermediates in organic reactions.

### Step 6: Hydrolysis of Isocyanate
The isocyanate (R-N=C=O) undergoes hydrolysis in the presence of water, resulting in the formation of the final product, which is an amine (RNH2) and carbon dioxide (CO2).

**Hint:** Consider the role of water in converting isocyanate into a more stable product.

### Conclusion: Identifying the Intermediates
From the steps outlined, we can identify the intermediates formed during the reaction:
1. R-C(=O)-NH-Br (bromamide)
2. R-N=C=O (isocyanate)

Thus, the correct intermediates from the options provided are:
- (a) RCONHBr
- (c) R-N=C=O

### Final Answer:
The correct intermediates are (a) RCONHBr and (c) R-N=C=O.