Which of the following characteristics identifies calcium carbonate?

The identification of calcium carbonate is accurately represented by its reaction with hydrochloric acid (HCl), which results in fizzing or bubbling due to the release of carbon dioxide gas. When calcium carbonate, a white powdery solid, comes into contact with HCl, the reaction produces calcium chloride, water, and carbon dioxide—making it distinctive from other substances that might appear similar. This property is a key indicator used in laboratories and various applications to confirm the presence of calcium carbonate.

In contrast, the other characteristics do not apply to calcium carbonate. The melting characteristic associated with high heat is not typical for calcium carbonate, which rather decomposes before melting. The clarification of a colorless solution in sunlight and changes in color with air do not pertain to calcium carbonate, which does not produce such effects. Hence, the fizzing reaction with HCl stands out as the definitive characteristic for identifying calcium carbonate.