Which of the following statements is correct?

Options

A. Elements of group 15 form electron deficient hydrides
B. All elements of group 14 form electron precise hydrides.
C. Electron precise hydrides have tetrahedral geometries.
D. Electron rich hydrides can act as Lewis acids.

Explanation

To determine which of the statements regarding hydrides is correct, we need to understand the classifications of hydrides: electron-deficient, electron-precise, and electron-rich hydrides.

### Step-by-Step Solution:

1. **Identify Types of Hydrides**:
- **Electron-Deficient Hydrides**: These hydrides have a central atom with an incomplete octet. A common example is boron hydrides (e.g., BH3).
- **Electron-Precise Hydrides**: These hydrides have the exact number of electrons required to form covalent bonds. An example is methane (CH4), which has a regular tetrahedral geometry.
- **Electron-Rich Hydrides**: These hydrides have more electrons than required for bonding, often acting as Lewis bases. An example is ammonia (NH3).

2. **Evaluate the Statements**:
- **Statement 1**: Electron-deficient hydrides belong to group 13 (e.g., boron hydrides).
- **Statement 2**: Electron-precise hydrides belong to group 14 (e.g., methane).
- **Statement 3**: Electron-rich hydrides such as ammonia are Lewis bases and not acids.

3. **Determine Correctness**:
- **Statement 1** is correct because boron hydrides are indeed electron-deficient.
- **Statement 2** is correct because methane is an example of an electron-precise hydride.
- **Statement 3** is also correct as ammonia acts as a Lewis base.

4. **Conclusion**:
- All the statements regarding hydrides are correct.

### Final Answer:
All of the statements provided are correct.