Interstital hydrides are formed by

Options

A. s-block metals
B. p-block metals
C. d-block metals
D. All of these

Answer

To solve the question "Interstitial hydrides are formed by," we will analyze the types of hydrides and identify which elements are responsible for forming interstitial hydrides.

### Step-by-Step Solution:

1. **Understand the Types of Hydrides**:
- There are three main types of hydrides:
- Ionic hydrides (also known as saline hydrides)
- Molecular hydrides (also known as covalent hydrides)
- Metallic hydrides (also known as interstitial hydrides)

2. **Identify the Elements Forming Each Type of Hydride**:
- **Ionic Hydrides**: Formed by s-block elements (e.g., alkali and alkaline earth metals). These elements react with hydrogen to form ionic compounds.
- **Molecular Hydrides**: Formed by p-block elements (except for noble gases). These elements typically form covalent bonds with hydrogen.
- **Metallic/Interstitial Hydrides**: Formed by d-block and f-block elements. These metals can absorb hydrogen into their lattice structure, resulting in interstitial hydrides.

3. **Determine Which Elements Form Interstitial Hydrides**:
- Since interstitial hydrides are specifically formed by d-block elements (transition metals) and some f-block elements, we can conclude that the correct answer pertains to these groups of elements.

4. **Evaluate the Options**:
- Option 1: S-block elements - Incorrect (they form ionic hydrides).
- Option 2: P-block elements - Incorrect (they form molecular hydrides).
- Option 3: D-block elements - Correct (they form interstitial hydrides).
- Option 4: All of the above - Incorrect (only d-block elements form interstitial hydrides).

5. **Conclusion**:
- The correct answer is that interstitial hydrides are formed by d-block elements.

### Final Answer:
Interstitial hydrides are formed by **d-block elements**.