Which of the following is a covalent solid ?

Options

A. Dry ice
B. `P_4O_10`
C. SiC
D. NaCl

Answer

To determine which of the given options is a covalent solid, we can analyze each substance based on its bonding characteristics.

### Step-by-Step Solution:

1. **Identify the substances**: The options given are:
- Dry ice (CO₂)
- P₄O₁₀
- Silicon carbide (SiC)
- Sodium chloride (NaCl)

2. **Analyze Dry Ice (CO₂)**:
- Dry ice is the solid form of carbon dioxide. It consists of discrete molecules held together by weak van der Waals forces (London dispersion forces).
- **Bonding type**: Molecular solid.
- **Conclusion**: Not a covalent solid.

3. **Analyze P₄O₁₀**:
- P₄O₁₀, also known as phosphorus pentoxide, is a molecular solid that consists of discrete P₄O₁₀ molecules.
- **Bonding type**: Molecular solid.
- **Conclusion**: Not a covalent solid.

4. **Analyze Silicon Carbide (SiC)**:
- Silicon carbide is a compound made of silicon and carbon atoms. In silicon carbide, silicon and carbon are bonded together through strong covalent bonds, forming a three-dimensional network.
- **Bonding type**: Covalent solid.
- **Conclusion**: This is a covalent solid.

5. **Analyze Sodium Chloride (NaCl)**:
- Sodium chloride is an ionic compound composed of sodium ions (Na⁺) and chloride ions (Cl⁻) held together by ionic bonds in a crystal lattice structure.
- **Bonding type**: Ionic solid.
- **Conclusion**: Not a covalent solid.

6. **Final Conclusion**:
- Among the given options, the only substance that qualifies as a covalent solid is **Silicon Carbide (SiC)**.

### Answer:
The covalent solid among the options is **Silicon Carbide (SiC)**.

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