`CH_(3)-CH_(2)-underset(O)underset(||)C-NH_(2)overset(A)rarrCH_(3)-CH_(2)-NH_(2)`
`overset(B)rarrCH_(3)-CH_(2)-OH`
In the above sequence A `&` B respectively are-

Options

A. `Br_(2)//KOH,NaOH`
B. `Br_(2)//KOH,HNO_(2)`
C. `KMnO_(4),KOH`
D. `HNO_(2),Br_(2)//KOH`

Answer

To solve the question, we need to identify the reactions represented by A and B in the conversion sequence:

1. **Starting Compound**: CH₃-CH₂-C(=O)-NH₂ (This is a primary amide).
2. **Final Products**: CH₃-CH₂-NH₂ (This is a primary amine) and CH₃-CH₂-OH (This is a primary alcohol).

### Step 1: Identify Reaction A
The conversion from a primary amide to a primary amine can be achieved through the Hofmann degradation reaction. In this reaction, the amide is treated with bromine (Br₂) in the presence of a strong base like potassium hydroxide (KOH).

**Reaction A**:
- **Reagents**: Br₂ and KOH
- **Process**: The amide reacts to form a primary amine by losing one carbon atom. The reaction involves the formation of an intermediate that rearranges and undergoes hydrolysis to yield the amine.

### Step 2: Identify Reaction B
The conversion from a primary amine to a primary alcohol can be achieved by treating the amine with nitrous acid (HNO₂). This reaction leads to the formation of an alcohol along with nitrogen gas and water.

**Reaction B**:
- **Reagents**: HNO₂ (Nitrous acid)
- **Process**: The primary amine reacts with nitrous acid to form the corresponding alcohol, nitrogen gas, and water.

### Final Answer
Thus, the reactions A and B respectively are:
- **A**: Br₂ + KOH (Hofmann degradation)
- **B**: HNO₂ (Nitrous acid reaction)

### Summary of Steps
1. Identify the starting compound as a primary amide.
2. Recognize that the conversion to a primary amine involves Hofmann degradation (Br₂ + KOH).
3. Identify that the conversion from a primary amine to a primary alcohol involves treatment with nitrous acid (HNO₂).