How many of the following are saline hydrides?
`CH_(4),NaH, HF, CrH, PdH_(0.7), LiH, CaH_(2),TiH_(1.6)`

Answer

To determine how many of the given compounds are saline hydrides, we need to first understand what saline hydrides are. Saline hydrides are ionic hydrides formed by the combination of hydrogen with alkali metals (Group 1) and alkaline earth metals (Group 2).

Let's analyze each compound in the list:

1. **CH₄ (Methane)**: This is a covalent compound and not a hydride of an alkali or alkaline earth metal. Therefore, it is not a saline hydride.

2. **NaH (Sodium Hydride)**: Sodium is an alkali metal (Group 1), and NaH is an ionic hydride. Thus, it is a saline hydride.

3. **HF (Hydrofluoric Acid)**: This is a covalent compound and not a hydride of an alkali or alkaline earth metal. Therefore, it is not a saline hydride.

4. **CrH (Chromium Hydride)**: This compound is not formed from an alkali or alkaline earth metal. It is a transition metal hydride and is not classified as a saline hydride.

5. **PdH₀.₇ (Palladium Hydride)**: Similar to CrH, this is a hydride of a transition metal and is not a saline hydride.

6. **LiH (Lithium Hydride)**: Lithium is an alkali metal (Group 1), and LiH is an ionic hydride. Thus, it is a saline hydride.

7. **CaH₂ (Calcium Hydride)**: Calcium is an alkaline earth metal (Group 2), and CaH₂ is an ionic hydride. Thus, it is a saline hydride.

8. **TiH₁.₆ (Titanium Hydride)**: This compound is a hydride of a transition metal and is not classified as a saline hydride.

Now, let's summarize the findings:

- Saline hydrides identified: NaH, LiH, CaH₂
- Total number of saline hydrides: 3

Thus, the answer to the question is that there are **3 saline hydrides** in the given list.