Which of the following is covalent solid.

Options

A. Solid `CO_(2)`
B. Graphite
C. Diamond
D. 2 & 3 both

Answer

To determine which of the following is a covalent solid, we need to analyze the characteristics of covalent solids and the examples provided. Here’s a step-by-step solution:

### Step 1: Understand Covalent Solids
Covalent solids, also known as network solids, are crystalline solids where the constituent particles are non-metals. These particles are bonded together by covalent bonds, which are formed by the sharing of electrons.

**Hint:** Covalent solids are characterized by a network of covalent bonds throughout the structure.

### Step 2: Identify Common Examples
One of the most common examples of a covalent solid is diamond. In diamond, carbon atoms are arranged in a three-dimensional structure, where each carbon atom is covalently bonded to four other carbon atoms.

**Hint:** Look for structures that have a network of covalent bonds, such as diamond.

### Step 3: Analyze Other Examples
Graphite is another example of a covalent solid, where carbon atoms are arranged in layers with hexagonal bonding. Although graphite conducts electricity due to the presence of delocalized electrons, it is still classified as a covalent solid.

**Hint:** Remember that some covalent solids can have unique properties, like conductivity in graphite.

### Step 4: Consider Other Solids
When considering other solids such as solid CO2 (dry ice), it is important to note that dry ice is a molecular solid, not a covalent solid. In molecular solids, the constituent particles are molecules rather than atoms bonded in a network.

**Hint:** Differentiate between molecular solids and covalent solids based on their constituent particles.

### Step 5: Conclusion
Based on the analysis, the covalent solids among the options provided are diamond and graphite. Therefore, the answer to the question is that both diamond and graphite are covalent solids.

**Final Answer:** Diamond and graphite are covalent solids.