In Hogmann degradation of amide the correct order of reagent is :

Options

A. `Br_2, KOH ,H_2o`
B. ` KOH , Br _2 , H_2O`
C. ` H_2 o, KOH , Br _2 `
D. None of these

Answer

To solve the question regarding the correct order of reagents used in the Hofmann degradation of amides, we will break down the process step by step.

### Step-by-Step Solution:

1. **Identify the Reaction**: The Hofmann degradation is a chemical reaction that involves the conversion of an amide to a primary amine. The reaction typically involves bromine (Br2) and a strong base such as potassium hydroxide (KOH).

2. **Reagents Involved**: The key reagents in the Hofmann degradation are:
- KOH (potassium hydroxide)
- Br2 (bromine)
- Water (H2O)

3. **Order of Reagents**:
- **First Step**: The reaction begins with the addition of KOH. The hydroxide ions (OH-) from KOH act as a base and abstract a proton from the amide, creating a negatively charged intermediate.
- **Second Step**: Next, Br2 is added. The negatively charged intermediate reacts with bromine, leading to the formation of an acyl bromide.
- **Third Step**: Finally, water is involved in the reaction. The acyl bromide undergoes hydrolysis, resulting in the formation of a primary amine and the release of carbon dioxide (CO2).

4. **Final Order of Reagents**: Based on the steps outlined above, the correct order of reagents used in the Hofmann degradation of amides is:
- KOH (first)
- Br2 (second)
- Water (third)

5. **Conclusion**: Therefore, the correct answer is option B: KOH, Br2, and water.