Which of the following is electron precise hydride ?

Options

A. `BH_(3)`
B. `CH_(4)`
C. `H_(2)O`
D. HF

Answer

To determine which of the following is an electron-precise hydride, we need to analyze each option based on their electron configuration and bonding characteristics. The options given are:

1. BH3 (Boron Hydride)
2. CH4 (Methane)
3. H2 (Hydrogen)
4. HF (Hydrogen Fluoride)

### Step-by-Step Solution:

**Step 1: Understand the Types of Hydrides**
- Hydrides can be classified into three categories: ionic, molecular, and metallic hydrides.
- Ionic hydrides are formed by group 1 and group 2 metals with hydrogen.
- Molecular hydrides are formed by p-block elements (groups 13 to 17) with hydrogen.
- Metallic hydrides are formed by d and f block elements with hydrogen.

**Step 2: Classify the Given Hydrides**
- **BH3 (Boron Hydride)**: This is a molecular hydride formed by boron (group 13). It is known to be electron deficient because boron does not complete its octet.
- **CH4 (Methane)**: This is also a molecular hydride formed by carbon (group 14). It is electron precise because carbon shares four electrons with hydrogen, completing its octet.
- **H2 (Hydrogen)**: This is a diatomic molecule of hydrogen and does not fit into the category of electron-precise hydrides.
- **HF (Hydrogen Fluoride)**: This is a molecular hydride formed by fluorine (group 17). It is considered electron-rich because fluorine has a complete octet and also has a lone pair.

**Step 3: Identify the Electron-Precise Hydride**
- Among the options, CH4 (Methane) is the only hydride that is electron precise, meaning it has a complete octet and does not have any electron deficiency or excess.

### Conclusion:
The correct answer is **CH4 (Methane)**, which is the electron-precise hydride.

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