Which of the following is the correct order for increasing bond angle ?

Options

A. `Nh_(3) lt PH_(3) lt AsH_(3) lt SbH_(3)`
B. `H_(2)O lt OF_(2) lt Cl_(2)O`
C. `H_(2)Te^(+) lt H_(3)Se^(+) lt H_(3)S^(+) lt H_(3)O^(+)`
D. `BF_(3) lt BCl_(3) lt BBr_(3) lt BI_(3)`

Explanation

To determine the correct order for increasing bond angles among the given compounds, we will analyze the bond angles based on the central atom's electronegativity and the presence of lone pairs.

### Step-by-Step Solution:

1. **Identify the Compounds**: The compounds given are NH3 (Ammonia), PH3 (Phosphine), ASH3 (Arsine), and SBH3 (Stibine). These compounds are hydrides of nitrogen, phosphorus, arsenic, and antimony respectively.

2. **Understand the Trend in Electronegativity**: As we move down the group in the periodic table from nitrogen to antimony, the electronegativity decreases. This means that the ability of the central atom to attract bonding electrons decreases.

3. **Impact on Electron Density**: With decreasing electronegativity, the electron density around the central atom also decreases. This results in less repulsion between the bonding pairs of electrons.

4. **Bond Angle Analysis**:
- **NH3** has the highest bond angle due to nitrogen's high electronegativity and the presence of a lone pair, which creates a strong repulsion with the bonding pairs.
- **PH3** has a lower bond angle than NH3 because phosphorus is less electronegative than nitrogen, leading to decreased electron density and less repulsion.
- **ASH3** and **SBH3** will have even lower bond angles due to further decrease in electronegativity and electron density.

5. **Order of Bond Angles**: Therefore, the order of increasing bond angles for these compounds is:
- SBH3 < ASH3 < PH3 < NH3.

6. **Conclusion**: The correct order for increasing bond angle is NH3, PH3, ASH3, SBH3.