Which one of the following is not a base

Options

A. `N_(2)H_(4)`
B. `NH_(2)OH`
C. `(CH_(3))_(3)N`
D. `HN_(3)`

Answer

To determine which compound is not a base among the given options, we need to analyze the properties of each compound in terms of their ability to donate a lone pair of electrons. A base is typically defined as a substance that can accept protons (H⁺) or donate a pair of valence electrons.

### Step-by-Step Solution:

1. **Identify the Compounds**: We need to evaluate the given compounds. Let's consider the following:
- N2H4 (Hydrazine)
- CH3 (Methyl group)
- CH3CH3 (Ethane)
- HN3 (Hydrazoic acid)

2. **Analyze N2H4 (Hydrazine)**:
- Hydrazine has nitrogen atoms that can donate lone pairs of electrons.
- It can act as a base due to the presence of nitrogen, which is less electronegative than oxygen and readily donates its lone pair.
- **Conclusion**: N2H4 is a base.

3. **Analyze CH3 (Methyl group)**:
- The methyl group (CH3) does not have a lone pair of electrons to donate.
- It is not a base as it cannot accept protons or donate electrons.
- **Conclusion**: CH3 is not a base.

4. **Analyze CH3CH3 (Ethane)**:
- Ethane (CH3CH3) is a saturated hydrocarbon with no lone pairs of electrons available for donation.
- Similar to the methyl group, it cannot act as a base.
- **Conclusion**: CH3CH3 is not a base.

5. **Analyze HN3 (Hydrazoic acid)**:
- Hydrazoic acid has nitrogen atoms that can donate lone pairs, but it also has acidic properties.
- It is primarily known for its acidic behavior rather than basicity.
- **Conclusion**: HN3 is not a base.

6. **Final Evaluation**:
- Among the compounds analyzed, both CH3 and CH3CH3 do not act as bases.
- However, HN3 is specifically noted for its acidic properties and is not considered a base.

### Answer:
The compound that is not a base is **HN3 (Hydrazoic acid)**.