Which of the following cannot react with ` HNO_2`?

Options

A. `CH_3CONH_2`
B. `(CH_3)_3CNO_2`
C. `(CH_3CH_2)_2NH`
D. `CH_3CH_2NH_2`

Explanation

To determine which of the given compounds cannot react with nitrous acid (HNO₂), we will analyze each option based on their chemical structure and reactivity with HNO₂.

### Step-by-Step Solution:

1. **Identify the Compounds**:
- We have four options to consider:
- Option A: Acetamide (CH₃CONH₂)
- Option B: A tertiary nitroalkane (e.g., 2-nitropropane)
- Option C: A secondary amine (e.g., C₂H₅NHCH₃)
- Option D: A primary amine (e.g., ethanamine, C₂H₅NH₂)

2. **Reactivity of Acetamide with HNO₂**:
- Acetamide reacts with nitrous acid to form acetic acid, nitrogen gas, and water.
- **Reaction**: CH₃CONH₂ + HNO₂ → CH₃COOH + N₂ + H₂O
- **Conclusion**: Acetamide can react with HNO₂.

3. **Reactivity of Tertiary Nitroalkane with HNO₂**:
- Tertiary nitroalkanes do not react with nitrous acid. This is because the carbon attached to the nitro group (NO₂) is tertiary, and such compounds are resistant to nucleophilic attack by HNO₂.
- **Conclusion**: Tertiary nitroalkane cannot react with HNO₂.

4. **Reactivity of Secondary Amine with HNO₂**:
- Secondary amines react with nitrous acid to form nitroso compounds.
- **Reaction**: R₂NH + HNO₂ → R₂N=O + H₂O
- **Conclusion**: Secondary amines can react with HNO₂.

5. **Reactivity of Primary Amine with HNO₂**:
- Primary amines react with nitrous acid to produce alcohols, nitrogen gas, and water.
- **Reaction**: RNH₂ + HNO₂ → R-OH + N₂ + H₂O
- **Conclusion**: Primary amines can react with HNO₂.

6. **Final Conclusion**:
- Among the options, the compound that cannot react with HNO₂ is the tertiary nitroalkane (Option B).

### Final Answer:
The compound that cannot react with HNO₂ is **Option B: Tertiary Nitroalkane**.