Determine the incorrect order of bond angle ?

Options

A. `NH_(3)ltNF_(3)ltNCl_(3)`
B. `OF_(2)ltOH_(2)ltOCl_(2)`
C. `SF_(2)ltSCl_(2)ltSBr_(2)ltSI_(2)`
D. `ClO_(2)^(-1)ltOCl_(2)`

Answer

To determine the incorrect order of bond angles among the given molecules (NH3, NF3, NCl3), we need to analyze the bond angles based on the molecular geometry and the effects of electronegativity and lone pairs.

### Step-by-Step Solution:

1. **Identify the Structures**:
- NH3 (Ammonia): Has a trigonal pyramidal shape due to one lone pair on nitrogen.
- NF3 (Nitrogen trifluoride): Also has a trigonal pyramidal shape, but with three fluorine atoms.
- NCl3 (Nitrogen trichloride): Similar trigonal pyramidal shape, but with three chlorine atoms.

2. **Consider Electronegativity**:
- Fluorine (F) is more electronegative than chlorine (Cl) and hydrogen (H). This means that in NF3, the bond electrons are pulled closer to the fluorine atoms, resulting in less repulsion between the bonding pairs compared to NH3.
- In NH3, the hydrogen atoms are less electronegative, which allows for greater repulsion between the lone pair and the bonding pairs, leading to a larger bond angle.

3. **Analyze Bond Angles**:
- NH3 typically has a bond angle of approximately 107 degrees.
- NF3 has a bond angle of about 102 degrees due to the strong electronegativity of fluorine.
- NCl3 has a bond angle of approximately 107 degrees, similar to NH3, but the larger size of chlorine leads to less repulsion compared to fluorine.

4. **Order the Bond Angles**:
- From the analysis, we can deduce the following order of bond angles:
- NH3 > NCl3 > NF3
- This means that NH3 has the largest bond angle, followed by NCl3, and then NF3 with the smallest bond angle.

5. **Identify the Incorrect Order**:
- If any order suggests that NF3 has a larger bond angle than NH3 or NCl3, that would be incorrect. The correct order based on our analysis is NH3 > NCl3 > NF3.

### Conclusion:
The incorrect order of bond angles among NH3, NF3, and NCl3 is likely to be one that places NF3 above NH3 or NCl3, which contradicts the established bond angle hierarchy.