Among the hydrides given below which are reasonable good acids?

Options

A. `NH_(3)`
B. `HF`
C. `HCl`
D. `NaH`

Answer

To determine which of the given hydrides are reasonable good acids, we will analyze each hydride based on its properties and classification.

### Step-by-Step Solution:

1. **Identify the Hydrides**: The hydrides provided are NH3 (ammonia), HF (hydrofluoric acid), HCl (hydrochloric acid), and NaH (sodium hydride).

2. **Classify NaH**:
- NaH is an alkali metal hydride.
- It is formed by the transfer of an electron from sodium (Na) to hydrogen (H), resulting in an ionic bond.
- **Conclusion**: NaH is not acidic; it is classified as a basic hydride.

3. **Analyze NH3**:
- NH3 is a hydride of nitrogen (a group 15 element).
- It has a lone pair of electrons on nitrogen, which makes it a Lewis base.
- **Conclusion**: NH3 is basic in nature and not classified as an acid.

4. **Analyze HF**:
- HF is a covalent hydride where hydrogen is bonded to fluorine, a highly electronegative atom.
- HF can donate a proton (H+) in solution, which is a characteristic of acids.
- **Conclusion**: HF is a reasonable good acid.

5. **Analyze HCl**:
- HCl is also a covalent hydride, where hydrogen is bonded to chlorine.
- HCl is a strong acid and readily donates a proton in solution.
- **Conclusion**: HCl is a strong acid and thus a reasonable good acid.

6. **Final Conclusion**:
- Among the given hydrides, the reasonable good acids are HF and HCl.

### Summary of Answers:
- **Reasonable Good Acids**: HF and HCl.