The hydride which doesno't act as reducing agent is

Options

A. `NH_(3)`
B. `CaH_(2)`
C. `NaH`
D. `LiAIH_(4)`

Answer

To solve the question regarding which hydride does not act as a reducing agent, we will analyze each hydride mentioned and determine their reducing properties.

### Step-by-Step Solution:

1. **Understanding Reducing Agents**:
- A reducing agent is a substance that donates electrons to another substance, thereby reducing it. In the process, the reducing agent itself gets oxidized.

2. **Analyzing Ammonia (NH₃)**:
- Ammonia has a nitrogen atom with a lone pair of electrons.
- It can donate these electrons to electron-deficient compounds, acting as a nucleophile.
- Therefore, ammonia can act as a reducing agent.

3. **Analyzing Calcium Hydride (CaH₂)**:
- Calcium hydride dissociates to produce calcium ions (Ca²⁺) and hydride ions (H⁻).
- The hydride ions can donate electrons to reduce other substances, such as metal oxides.
- Thus, calcium hydride acts as a reducing agent.

4. **Analyzing Sodium Hydride (NaH)**:
- Sodium hydride also produces hydride ions (H⁻).
- However, the hydride ion in sodium hydride does not have the capacity to reduce carbonyl compounds (C=O).
- Instead, it primarily acts as a base and does not function as a reducing agent.
- Therefore, sodium hydride does not act as a reducing agent.

5. **Analyzing Lithium Aluminum Hydride (LiAlH₄)**:
- Lithium aluminum hydride is known as a very strong reducing agent.
- It can reduce carbonyl compounds to primary or secondary alcohols effectively.
- Hence, lithium aluminum hydride acts as a reducing agent.

6. **Conclusion**:
- Among the hydrides analyzed, sodium hydride (NaH) is the one that does not act as a reducing agent.
- Therefore, the correct answer is sodium hydride.

### Final Answer:
The hydride which does not act as a reducing agent is **Sodium Hydride (NaH)**.

---