Which of the following is//are convalent solids?

Options

A. `Fe`
B. Diamond
C. `NaCl`
D. Graphite

Answer

To determine which of the given substances are covalent solids, we need to understand the characteristics of covalent solids. Here’s a step-by-step solution:

### Step 1: Understand the Definition of Covalent Solids
Covalent solids are materials where the atoms are bonded together by covalent bonds. These solids typically consist of non-metals and exhibit the following characteristics:
- They are hard due to the strength of covalent bonds.
- They have high melting points.
- They do not conduct electricity.

### Step 2: Analyze Each Option
Now, let’s analyze each of the given options to determine if they are covalent solids.

1. **Fe (Iron)**:
- Iron is a metal.
- **Conclusion**: Not a covalent solid.

2. **Diamond**:
- Diamond is a form of carbon where each carbon atom is covalently bonded to four other carbon atoms in a tetrahedral structure.
- **Conclusion**: Diamond is a covalent solid.

3. **Graphite**:
- Graphite is another form of carbon. In graphite, each carbon atom is bonded to three others in layers, with weak forces between the layers.
- **Conclusion**: Graphite is a covalent solid.

4. **NaCl (Sodium Chloride)**:
- NaCl is an ionic compound, consisting of sodium and chloride ions. It conducts electricity when dissolved in water.
- **Conclusion**: Not a covalent solid.

### Step 3: Summarize the Findings
Based on the analysis:
- **Covalent Solids**: Diamond and Graphite
- **Not Covalent Solids**: Iron (Fe) and Sodium Chloride (NaCl)

### Final Answer
The covalent solids among the options provided are **Diamond and Graphite**.

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