The correct order of bond angles (smallest first) in:

Options

A. `H_(2)S lt NH_(3)SiH_(4) lt BF_(3)`
B. `NH_(3) lt H_(2)S lt SiH_(4) lt BF_(3)`
C. `H_(2)S lt SiH_(4) lt NH_(3) lt BF_(3)`
D. `H_(2)S lt NH_(3) lt BF_(3) lt SiH_(4)`

Explanation

To determine the correct order of bond angles (from smallest to largest) for the given molecules (H₂S, NH₃, SiH₄, and VF₃), we can analyze each molecule based on its molecular geometry and the presence of lone pairs.

### Step-by-Step Solution:

1. **Identify the Molecular Geometries**:
- **H₂S (Hydrogen Sulfide)**: The molecular geometry is bent due to the presence of two lone pairs on sulfur. The bond angle is approximately 90°.
- **NH₃ (Ammonia)**: The molecular geometry is trigonal pyramidal because of one lone pair on nitrogen. The bond angle is approximately 107°.
- **SiH₄ (Silane)**: The molecular geometry is tetrahedral with no lone pairs. The bond angle is approximately 109.5°.
- **VF₃ (Vanadium Trifluoride)**: The molecular geometry is also trigonal pyramidal (similar to NH₃) but with a larger central atom. The bond angle is approximately 120°.

2. **Compare the Bond Angles**:
- H₂S: 90°
- NH₃: 107°
- SiH₄: 109.5°
- VF₃: 120°

3. **Order the Bond Angles from Smallest to Largest**:
- The smallest bond angle is from H₂S (90°).
- The next is NH₃ (107°).
- Followed by SiH₄ (109.5°).
- The largest bond angle is from VF₃ (120°).

4. **Final Order**:
- The correct order of bond angles from smallest to largest is:
- H₂S < NH₃ < SiH₄ < VF₃

5. **Select the Correct Option**:
- Based on the analysis, the correct option that reflects this order is option number 1.