Which of the following is a good conductor of electricity?

Options

A. Diamond
B. Graphite
C. Solid NaCl
D. Wood

Answer

To determine which of the given options is a good conductor of electricity, we need to analyze the properties of each material in terms of their ability to allow the flow of electric current. A good conductor typically has free-moving electrons or ions that can carry charge.

### Step-by-Step Solution:

1. **Understanding Conductivity**:
- Conductivity in materials is primarily due to the presence of free-moving charged particles, which can be either electrons or ions.

2. **Analyzing Diamond**:
- Diamond is an allotrope of carbon with a tetrahedral structure.
- In diamond, each carbon atom is bonded to four other carbon atoms through strong covalent bonds.
- There are no free electrons or ions present in diamond, making it a poor conductor of electricity.

3. **Analyzing Graphite**:
- Graphite is another allotrope of carbon, but its structure is different from that of diamond.
- In graphite, carbon atoms are arranged in layers with weak intermolecular forces between them.
- Each carbon atom in graphite is bonded to three other carbon atoms, leaving one electron free (delocalized).
- These delocalized electrons can move freely within the layers, allowing graphite to conduct electricity effectively.

4. **Analyzing Sodium Chloride (NaCl)**:
- Solid NaCl consists of a tightly packed ionic lattice structure.
- In solid form, NaCl does not have free-moving ions since they are fixed in place within the lattice.
- Therefore, solid NaCl is not a good conductor of electricity.

5. **Analyzing Wood**:
- Wood is an organic material composed of cellulose and lignin.
- It does not contain free-moving charged particles (ions or electrons) and is considered an insulator.
- Thus, wood does not conduct electricity.

6. **Conclusion**:
- Among the materials analyzed, graphite is the only one that has free-moving electrons, making it a good conductor of electricity.
- Therefore, the correct answer is **graphite**.

### Final Answer:
**Graphite is a good conductor of electricity.**

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