Which of the following compounds contains no covalent bond(s)?
`NaCl, PH_(3),O_(2),B_(2)H_(6),H_(2)SO_(4),CaCl_(2)`

Options

A. `NaCl, B_(2)H_(6)`
B. `NaCl, B_(2)H_(6),PH_(3)`
C. `NaCl, H_(2)SO_(4)`
D. `NaCl, CaCl_(2)`

Answer

To determine which of the given compounds contains no covalent bonds, we need to analyze each compound and identify the type of bonding present.

### Step-by-Step Solution:

1. **Understanding Covalent vs Ionic Bonds**:
- Covalent bonds are formed by the sharing of electrons between atoms.
- Ionic bonds are formed when one atom donates an electron to another atom, resulting in the formation of charged ions.

2. **Analyzing Each Compound**:
- **NaCl (Sodium Chloride)**:
- Sodium (Na) has one electron in its outer shell and chlorine (Cl) has seven. Sodium donates its electron to chlorine, forming Na⁺ and Cl⁻ ions. This is an ionic bond.

- **PH₃ (Phosphine)**:
- Phosphorus (P) shares electrons with three hydrogen (H) atoms to form covalent bonds. Thus, PH₃ contains covalent bonds.

- **O₂ (Oxygen)**:
- O₂ consists of two oxygen atoms sharing two electrons (double bond). Therefore, O₂ contains covalent bonds.

- **B₂H₆ (Diborane)**:
- B₂H₆ is a dimer of BH₃, where boron shares electrons with hydrogen. It contains covalent bonds, including coordinate bonds.

- **H₂SO₄ (Sulfuric Acid)**:
- In H₂SO₄, sulfur shares electrons with oxygen and hydrogen, forming covalent bonds.

- **CaCl₂ (Calcium Chloride)**:
- Calcium (Ca) has two electrons in its outer shell and donates both to two chlorine atoms. This results in Ca²⁺ and Cl⁻ ions. Therefore, CaCl₂ is also an ionic compound.

3. **Conclusion**:
- The compounds NaCl and CaCl₂ are ionic and contain no covalent bonds. Therefore, the answer to the question is that both NaCl and CaCl₂ contain no covalent bonds.

### Final Answer:
The compounds that contain no covalent bonds are **NaCl and CaCl₂**.