Which bond is expected to be the least polar ?

Options

A. O-F
B. P-F
C. Si-N
D. B-F

Explanation

To determine which bond is expected to be the least polar, we need to analyze the electronegativity differences between the atoms involved in the bonds. The polarity of a bond is directly related to the difference in electronegativity between the two atoms forming the bond. The greater the difference, the more polar the bond will be.

### Step-by-Step Solution:

1. **Understand Polarity**:
- Polarity in a bond arises due to the difference in electronegativity between the two atoms. If one atom is more electronegative than the other, it will attract the shared electrons more strongly, creating a dipole moment.

2. **Identify Electronegativity Values**:
- We need to look up the electronegativity values of the relevant elements. Common values to remember are:
- Fluorine (F): 3.98
- Oxygen (O): 3.44
- Nitrogen (N): 3.04
- Carbon (C): 2.55
- Silicon (Si): 1.90
- Phosphorus (P): 2.19
- Boron (B): 2.04

3. **Calculate Electronegativity Differences**:
- For each pair of atoms, calculate the difference in their electronegativity values.
- For example:
- **Oxygen (O) and Fluorine (F)**: |3.44 - 3.98| = 0.54
- **Nitrogen (N) and Fluorine (F)**: |3.04 - 3.98| = 0.94
- **Phosphorus (P) and Fluorine (F)**: |2.19 - 3.98| = 1.79
- **Silicon (Si) and Nitrogen (N)**: |1.90 - 3.04| = 1.14
- **Boron (B) and Fluorine (F)**: |2.04 - 3.98| = 1.94

4. **Compare the Differences**:
- After calculating the differences, compare them to identify which pair has the smallest difference.
- From the calculations:
- O-F: 0.54
- N-F: 0.94
- P-F: 1.79
- Si-N: 1.14
- B-F: 1.94

5. **Identify the Least Polar Bond**:
- The bond with the smallest electronegativity difference is the least polar. In this case, the bond between Oxygen and Fluorine (O-F) has the smallest difference of 0.54, making it the least polar bond.

6. **Conclusion**:
- Therefore, the bond expected to be the least polar is the bond between Oxygen and Fluorine (O-F).

### Final Answer:
The bond expected to be the least polar is the bond between Oxygen and Fluorine (O-F).