Question

The compound insoluble in acetic acid is: (a) Calcium oxide (b) Calcium carbonate (c) Calcium oxalate (d) Calcium hydroxide

Short answer

Calcium oxalate (c) is insoluble in acetic acid.

Step-by-step solution

Understand the Task

We need to identify which calcium compound listed is insoluble in acetic acid. Insoluble means the compound will not dissolve in acetic acid.

Evaluate Solubility

Examine each compound's solubility: (a) Calcium oxide reacts with acetic acid to form calcium acetate, which is soluble. (b) Calcium carbonate reacts with acetic acid, releasing carbon dioxide gas and forming soluble calcium acetate. (c) Calcium oxalate is known to be insoluble in acetic acid. (d) Calcium hydroxide dissolves in acetic acid to form the soluble calcium acetate.

Identify the Answer

After evaluating the solubility of each compound in acetic acid, identify the compound that remains insoluble.

Confirm the Conclusion

Confirm that calcium oxalate (c) is the only compound from the list that remains insoluble in acetic acid.

Key concepts

Calcium Compounds

Calcium compounds are ubiquitous in nature and have various applications in industry and biological processes. Some common calcium compounds include calcium oxide, calcium carbonate, calcium oxalate, and calcium hydroxide. Each of these compounds has unique properties that determine its interaction with other substances, including its solubility.

• Calcium Oxide: Often known as quicklime, this compound is highly reactive and is used in cement and lime. It reacts with water to form calcium hydroxide.
• Calcium Carbonate: This is found naturally in rocks as minerals like calcite and aragonite, making up shells of marine organisms and eggs. It's commonly used in antacids and as a calcium supplement.
• Calcium Oxalate: Known for its role in kidney stones, this compound is found in many plants and is insoluble in water and weak acids like acetic acid.
• Calcium Hydroxide: Also called slaked lime, it is used in various industrial processes including water treatment and as a plaster and mortar component.

Solubility in Acetic Acid

Solubility is a chemical property defining the ability of a substance to dissolve in a solvent. Acetic acid, which is the main component of vinegar, can dissolve many substances, but not all. The solubility of calcium compounds in acetic acid depends on their chemical structure and the reaction they undergo when mixed with acetic acid.

• Calcium Oxide: Dissolves in acetic acid, forming calcium acetate, which is highly soluble.
• Calcium Carbonate: Reacts vigorously with acetic acid producing carbon dioxide and forming soluble calcium acetate.
• Calcium Oxalate: Remains largely insoluble, neither reacting significantly nor dissolving in acetic acid.
• Calcium Hydroxide: Converts to calcium acetate upon reaction with acetic acid, hence soluble.

Understanding these solubility characteristics assists in determining applications and handling of these compounds in practical scenarios.

Chemical Reactions with Acetic Acid

When calcium compounds interact with acetic acid, different reactions and outcomes occur based on the compound's reactivity and solubility. These reactions often lead to the formation of calcium acetate, known for its solubility.

• Calcium Oxide Reaction: When calcium oxide is added to acetic acid, it reacts to form water and calcium acetate, which dissolves in the solution.


• Calcium Carbonate Reaction: Involves a noticeable reaction where carbon dioxide bubbles evolve, indicative of the formation of calcium acetate.


• Calcium Oxalate Behavior: This compound does not undergo significant reaction, maintaining its solid form without dissolving in the acid.


• Calcium Hydroxide Reaction: Reacts smoothly with acetic acid to form water and the soluble calcium acetate.

These interactions highlight the diverse chemical behavior of calcium compounds and their practical implications in both industrial and laboratory settings.