`H^(Theta)` always act as

Options

A. Nucleophile
B. Base
C. Electrophile
D. Ambiphile

Answer

To solve the question "H⁻ (hydride ion) always acts as?", we need to analyze the properties of the hydride ion and its behavior in chemical reactions.

### Step-by-Step Solution:

1. **Identify the Nature of H⁻:**
- The hydride ion (H⁻) consists of a hydrogen atom that has gained an extra electron, giving it a negative charge.

2. **Determine the Role of H⁻ in Reactions:**
- H⁻ can act as a nucleophile. Nucleophiles are species that have a pair of electrons to donate, which allows them to form bonds with electrophiles (electron-deficient species).

3. **Consider the Basicity of H⁻:**
- H⁻ can also act as a base. A base is defined as a species that can accept protons (H⁺ ions). When H⁻ accepts a proton, it forms neutral hydrogen gas (H₂).

4. **Evaluate Other Possible Roles:**
- While H⁻ can act as a nucleophile and a base, it does not typically act as an electrophile because it is not electron-deficient. Electrophiles are species that accept electrons, and H⁻ has an excess of electrons.

5. **Conclusion:**
- Based on the analysis, the hydride ion (H⁻) primarily acts as a base because it can accept protons (H⁺) to form H₂ and can also act as a nucleophile by donating its electron pair in reactions.

### Final Answer:
H⁻ always acts as a **base**.

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