Which of the following hydrides are generally non-stoichiometric in nature?

Options

A. ionic hydrogen
B. molecular hydrides
C. interstitial hydrides
D. all of these

Answer

To determine which hydrides are generally non-stoichiometric in nature, we will analyze the three types of hydrides mentioned: ionic hydrides, molecular hydrides, and interstitial hydrides.

### Step-by-Step Solution:

1. **Identify the Types of Hydrides**:
- We have three types of hydrides to consider:
- Ionic Hydrides
- Molecular Hydrides
- Interstitial Hydrides

2. **Analyze Ionic Hydrides**:
- Ionic hydrides are formed by the combination of hydrogen with highly electropositive metals (like alkali and alkaline earth metals).
- These hydrides have a definite stoichiometry, meaning they have a fixed ratio of hydrogen to metal (e.g., NaH, CaH₂).
- **Conclusion**: Ionic hydrides are stoichiometric in nature.

3. **Analyze Molecular Hydrides**:
- Molecular hydrides are formed by covalent bonds between hydrogen and non-metals (like H₂O, NH₃).
- Similar to ionic hydrides, molecular hydrides also exhibit a fixed composition.
- **Conclusion**: Molecular hydrides are stoichiometric in nature.

4. **Analyze Interstitial Hydrides**:
- Interstitial hydrides are formed when hydrogen atoms occupy the interstitial spaces in the metal lattice of transition and inter-transition metals.
- These hydrides do not have a fixed stoichiometry; the amount of hydrogen absorbed can vary depending on conditions such as temperature and pressure.
- **Conclusion**: Interstitial hydrides are generally non-stoichiometric in nature.

5. **Final Answer**:
- Based on the analysis, the hydrides that are generally non-stoichiometric in nature are **Interstitial Hydrides**.