Predominantly ionic halide of N-family is -

Options

A. `BiF_(3)`
B. `BiCl_(3)`
C. `PF_(3)`
D. `NF_(3)`

Answer

To determine the predominantly ionic halide of the nitrogen family (Group 15), we need to analyze the ionic character of the halides formed by the elements in this group. The nitrogen family consists of nitrogen (N), phosphorus (P), arsenic (As), antimony (Sb), and bismuth (Bi). The halides we will consider are NF3, PF3, AsF3, SbF3, and BiF3.

### Step-by-Step Solution:

1. **Identify the Halides**: The halides of the nitrogen family we will consider are NF3, PF3, AsF3, SbF3, and BiF3. We will focus on the halides with fluorine (F) as it is the most electronegative halogen.

2. **Understand Ionic Character**: The ionic character of a compound depends on the size of the cation and the anion. Generally, larger cations and smaller anions lead to higher ionic character.

3. **Analyze Cations**: In the nitrogen family, as we move down the group from nitrogen to bismuth, the size of the cation increases:
- Nitrogen (N) → N³⁺ (smallest)
- Phosphorus (P) → P³⁺
- Arsenic (As) → As³⁺
- Antimony (Sb) → Sb³⁺
- Bismuth (Bi) → Bi³⁺ (largest)

4. **Compare Ionic Character**: Since the anion (F⁻) remains constant across these compounds, we can conclude that the ionic character will increase as we move down the group due to the increasing size of the cation:
- NF3 (N³⁺) has the least ionic character.
- PF3 (P³⁺) has more ionic character than NF3.
- AsF3 (As³⁺) has more ionic character than PF3.
- SbF3 (Sb³⁺) has more ionic character than AsF3.
- BiF3 (Bi³⁺) has the most ionic character among these.

5. **Consider Other Halides**: Now, we should compare BiF3 with other halides like BiCl3. The cation (Bi³⁺) is the same, but the anion differs:
- F⁻ (smaller) leads to higher ionic character than Cl⁻ (larger).
- Therefore, BiF3 will have a higher ionic character than BiCl3.

6. **Conclusion**: After analyzing the ionic character of the halides of the nitrogen family, we conclude that the predominantly ionic halide of the nitrogen family is **BiF3** (Bismuth trifluoride).

### Final Answer:
The predominantly ionic halide of the nitrogen family is **BiF3**.