In which compound covalent bond exists among the following?

Options

A. Magnesium chloride
B. Sodium chloride
C. Calcium oxide
D. Ethane

Explanation

To determine which compound contains a covalent bond among the given options, we need to analyze each compound and identify the type of bonding present.

### Step-by-Step Solution:

1. **Identify the Compounds:**
- Option A: Magnesium chloride (MgCl₂)
- Option B: Sodium chloride (NaCl)
- Option C: Calcium oxide (CaO)
- Option D: Ethane (C₂H₆)

2. **Analyze Magnesium Chloride (MgCl₂):**
- Magnesium (Mg) is a metal and chlorine (Cl) is a non-metal.
- In MgCl₂, magnesium loses two electrons to form Mg²⁺ ions, and each chlorine atom gains one electron to form Cl⁻ ions.
- This results in the formation of ionic bonds due to the transfer of electrons.
- **Conclusion:** MgCl₂ contains ionic bonds.

3. **Analyze Sodium Chloride (NaCl):**
- Sodium (Na) is also a metal and chlorine (Cl) is a non-metal.
- In NaCl, sodium loses one electron to form Na⁺ ions, and chlorine gains one electron to form Cl⁻ ions.
- This results in the formation of ionic bonds due to the transfer of electrons.
- **Conclusion:** NaCl contains ionic bonds.

4. **Analyze Calcium Oxide (CaO):**
- Calcium (Ca) is a metal and oxygen (O) is a non-metal.
- In CaO, calcium loses two electrons to form Ca²⁺ ions, and oxygen gains two electrons to form O²⁻ ions.
- This results in the formation of ionic bonds due to the transfer of electrons.
- **Conclusion:** CaO contains ionic bonds.

5. **Analyze Ethane (C₂H₆):**
- Ethane consists of carbon (C) and hydrogen (H) atoms.
- The structure of ethane can be represented as CH₃-CH₃, where each carbon atom is bonded to three hydrogen atoms and to each other through single covalent bonds.
- In ethane, electrons are shared between the carbon and hydrogen atoms.
- **Conclusion:** Ethane contains covalent bonds.

6. **Final Conclusion:**
- Among the given options, only ethane (C₂H₆) contains covalent bonds.

### Answer:
**The compound that contains covalent bonds is Ethane (Option D).**

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