Which of the following does not contain any coordinate bond ?

Options

A. `H _(3) O^(+)`
B. `BF_(4) ^(-)`
C. `HF _(2) ^(-)`
D. `NH_(4) ^(+)`

Explanation

To determine which of the given options does not contain any coordinate bond, we need to analyze each option based on the definition of a coordinate bond. A coordinate bond (or dative bond) is formed when one atom donates both of the electrons to be shared with another atom.

### Step-by-Step Solution:

1. **Understanding Coordinate Bonds**:
- A coordinate bond is formed when one atom provides both electrons for the bond. This typically occurs when one atom has a lone pair of electrons that it can donate.

2. **Analyzing H3O+ (Hydronium ion)**:
- Oxygen has 6 valence electrons and forms bonds with three hydrogen atoms.
- One of the hydrogen atoms is bonded through a coordinate bond, where oxygen donates a lone pair to form the bond.
- **Conclusion**: H3O+ contains a coordinate bond.

3. **Analyzing BF4- (Tetrafluoroborate ion)**:
- Boron has 3 valence electrons and forms bonds with four fluorine atoms.
- Boron can accept a lone pair from a fluorine atom to complete its octet, which results in a coordinate bond.
- **Conclusion**: BF4- contains a coordinate bond.

4. **Analyzing HF2- (Dihydrogen fluoride ion)**:
- Each hydrogen has 1 valence electron, and fluorine has 7 valence electrons.
- In HF2-, the fluorine can share its lone pair with hydrogen, but this does not involve a coordinate bond as both atoms share electrons equally.
- **Conclusion**: HF2- does not contain a coordinate bond.

5. **Analyzing NH4+ (Ammonium ion)**:
- Nitrogen has 5 valence electrons and forms bonds with four hydrogen atoms.
- One of the hydrogen atoms is bonded through a coordinate bond, where nitrogen donates a lone pair to form the bond.
- **Conclusion**: NH4+ contains a coordinate bond.

6. **Final Conclusion**:
- Among the options analyzed, HF2- is the only species that does not contain a coordinate bond.

### Answer:
**HF2- does not contain any coordinate bond.**