What is the chemical equation for vinegar and a eggshell?

When vinegar, which contains acetic acid (CH3COOH), comes in contact with the calcium carbonate (CaCO3), present in the eggshell, it undergoes a chemical reaction known as an acid-base reaction. The reaction is represented by the following equation:

2CH3COOH (vinegar) + CaCO3 (eggshell) → Ca(CH3COO)2 (calcium acetate) + H2O (water) + CO2 (carbon dioxide gas)

In this reaction, the acetic acid in vinegar acts as an acid, donating hydrogen ions (H+), while Calcium Carbonate acts as a base, accepting hydrogen ions. As a result, Calcium acetate is formed as a salt (calcium acetate), along with water and Carbon Dioxide gas. The characteristic fizzing or bubbling observed during this reaction is due to the release of Carbon Dioxide gas. Calcium Acetate is a soluble compound, and it remains dissolved in the vinegar.