The compound insoluble in acetic acid

Options

A. Calcium oxide
B. Calcium carbonate
C. Calcium oxalate
D. Calcium hydroxide

Explanation

To determine which compound is insoluble in acetic acid among the given options, we will analyze each compound one by one.

### Step 1: Identify the compounds
The options provided are:
1. Calcium oxide (CaO)
2. Calcium carbonate (CaCO₃)
3. Calcium oxalate (CaC₂O₄)
4. Calcium hydroxide (Ca(OH)₂)

### Step 2: Analyze solubility in acetic acid
- **Calcium oxide (CaO)**: This compound reacts with acetic acid to form calcium acetate, thus it is soluble in acetic acid.

- **Calcium carbonate (CaCO₃)**: This compound reacts with acetic acid to produce carbon dioxide, water, and calcium acetate, indicating that it is also soluble in acetic acid.

- **Calcium oxalate (CaC₂O₄)**: This compound is known to be insoluble in acetic acid. The reason for its insolubility is due to its high lattice energy and low solvation energy, which prevents it from dissolving in the solvent.

- **Calcium hydroxide (Ca(OH)₂)**: This compound is slightly soluble in acetic acid, forming calcium acetate and water.

### Step 3: Conclusion
Among the given options, calcium oxalate (CaC₂O₄) is the only compound that is insoluble in acetic acid.

### Final Answer
The compound that is insoluble in acetic acid is **Calcium oxalate (CaC₂O₄)**.

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