In which of the following species the interatomic bond angle is `109^(@)28'` ?

Options

A. `NH_(3),(BF_(4))^(-1)`
B. `(NH_(4))^(+), BF_(3)`
C. `NH_(3), BF_(4)`
D. `(NH_(2))^(-1), BF_(3)`

Explanation

To determine which of the given species has an interatomic bond angle of `109°28'`, we need to identify the molecular geometry of each species and check if it corresponds to a tetrahedral shape, which has a bond angle close to `109°28'`.

### Step-by-Step Solution:

1. **Understanding the Tetrahedral Geometry**:
- The bond angle of `109°28'` is characteristic of a tetrahedral molecular geometry. In a tetrahedral arrangement, a central atom is bonded to four other atoms, and the angles between the bonds are approximately `109.5°`.

2. **Identifying the Species**:
- We need to analyze the given options to see which species can exhibit tetrahedral geometry. The options provided are:
- A) NH3 and BF4^-
- B) NH4^+ and BF3
- C) NS2- and VF3

3. **Analyzing Each Option**:
- **Option A: NH3 and BF4^-**
- **NH3 (Ammonia)**: The structure of NH3 has a trigonal pyramidal shape due to the presence of a lone pair on nitrogen. The bond angles are approximately `107°`, not `109°28'`.
- **BF4^- (Tetrafluoroborate)**: The structure of BF4^- is tetrahedral, with bond angles of `109.5°`. This matches our required angle.

- **Option B: NH4^+ and BF3**
- **NH4^+ (Ammonium)**: This species has a tetrahedral shape with bond angles of `109.5°`. This matches our required angle.
- **BF3 (Boron Trifluoride)**: This species has a trigonal planar geometry with bond angles of `120°`, which does not match.

- **Option C: NS2- and VF3**
- **NS2-**: The geometry of this species is not commonly known, but it is likely not tetrahedral.
- **VF3 (Vanadium Trifluoride)**: This species has a trigonal bipyramidal geometry, which does not match our required angle.

4. **Conclusion**:
- From the analysis, we find that both **BF4^-** and **NH4^+** exhibit tetrahedral geometry. However, since the question asks for a species with a bond angle of `109°28'`, we can conclude that **BF4^-** and **NH4^+** are valid candidates, but since the question likely refers to the most common example, **BF4^-** is the primary answer.

### Final Answer:
The species with an interatomic bond angle of `109°28'` is **BF4^-**.