Which of the following hydride is ionic ?

Options

A. `H_(2) O`
B. `NH_(3)`
C. `CaH_(2)`
D. `H_(2)S`

Explanation

To determine which hydride is ionic, we need to analyze the types of metals involved in the formation of hydrides. Ionic hydrides are typically formed by the reaction of hydrogen with active metals, particularly alkali metals and alkaline earth metals.

### Step-by-Step Solution:

1. **Identify the Types of Metals**:
- Ionic hydrides are formed by active metals, specifically alkali metals (Group 1) and alkaline earth metals (Group 2).
- Examples of alkali metals include lithium (Li), sodium (Na), and potassium (K).
- Examples of alkaline earth metals include beryllium (Be), magnesium (Mg), calcium (Ca), strontium (Sr), and barium (Ba).

2. **Recognize the Nature of Hydrides**:
- Hydrides can be classified into two categories: ionic hydrides and covalent hydrides.
- Ionic hydrides are formed when hydrogen combines with metals, while covalent hydrides are formed when hydrogen combines with nonmetals.

3. **Identify Ionic Hydrides**:
- Ionic hydrides are characterized by the presence of the hydride ion (H⁻).
- Examples include lithium hydride (LiH), sodium hydride (NaH), and calcium hydride (CaH₂).

4. **Determine the Correct Answer**:
- Among the hydrides mentioned, calcium hydride (CaH₂) is formed from the alkaline earth metal calcium, which is an active metal.
- Therefore, calcium hydride is classified as an ionic hydride.

5. **Conclusion**:
- The ionic hydride among the options is calcium hydride (CaH₂).

### Final Answer:
Calcium hydride (CaH₂) is the ionic hydride.