In which one of the following are both the covalent and coordinate bonds involved?

Options

A. `NH_3`
B. `H_2 O`
C. `NH_4^+`
D. `C_2 H_2`

Explanation

To determine which of the given options contains both covalent and coordinate bonds, we will analyze each option step by step.

### Step 1: Understand Covalent and Coordinate Bonds
- **Covalent Bond**: A bond formed when two atoms share one or more pairs of electrons.
- **Coordinate Bond (Dative Bond)**: A type of covalent bond where one atom provides both electrons for the bond.

### Step 2: Analyze Each Option
1. **NH3 (Ammonia)**:
- Structure: Nitrogen (N) is bonded to three Hydrogen (H) atoms.
- Type of Bonds: All bonds in NH3 are covalent bonds.
- Conclusion: **Only covalent bonds are present.**

2. **H2O (Water)**:
- Structure: Oxygen (O) is bonded to two Hydrogen (H) atoms, with two lone pairs on oxygen.
- Type of Bonds: All bonds in H2O are covalent bonds.
- Conclusion: **Only covalent bonds are present.**

3. **NiH4+ (Nickel Tetrahydride Ion)**:
- Structure: Nickel (Ni) is bonded to four Hydrogen (H) atoms.
- Type of Bonds: The bonds in NiH4+ include both covalent bonds and a coordinate bond. The coordinate bond is formed when Ni donates a pair of electrons to bond with H.
- Conclusion: **Both covalent and coordinate bonds are present.**

4. **C2H2 (Acetylene)**:
- Structure: Each Carbon (C) is triple bonded to another Carbon and single bonded to one Hydrogen.
- Type of Bonds: All bonds in C2H2 are covalent bonds.
- Conclusion: **Only covalent bonds are present.**

### Step 3: Final Conclusion
After analyzing all the options, the only compound that contains both covalent and coordinate bonds is **NiH4+**.

### Answer:
**NiH4+ (Nickel Tetrahydride Ion)** contains both covalent and coordinate bonds.

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