There will be a series of chemical reactions between eggshells and vinegar. This reaction is used to make a material called "eggshell calcium carbonate", which has many useful applications, such as pigments, cosmetics, jewelry and so on.

First of all, the main component of egg shell is calcium carbonate. When egg shells come into contact with vinegar, acetic acid in vinegar will react with calcium carbonate to produce calcium acetate, carbon dioxide and water. This reaction can be expressed as:

CaCO3 (egg shell) +2CH3COOH (vinegar) → Ca(CH3COO)2 (calcium acetate) +CO2 (carbon dioxide) +H2O (water).

This reaction can be carried out at room temperature and the reaction is reversible. Calcium acetate can be converted back to calcium carbonate if some sodium hydroxide solution is added.

This method of extracting calcium carbonate from eggshells has many advantages. First of all, eggshell is a rich and environmentally friendly raw material, and the extracted calcium carbonate has good biocompatibility and biodegradability. In addition, the calcium carbonate obtained by this method can be used to manufacture biodegradable plastics, biodegradable soil enhancers, etc.

The application of this reaction is not limited to the production of eggshell calcium carbonate. For example, after the egg shell is ground into powder, it can be used as fertilizer, because the egg shell is rich in nutrients, such as calcium and phosphorus. In addition, eggshells can also be used to make eggshell pottery, which has good thermal insulation effect and heat resistance.

In a word, the chemical reaction between egg shell and vinegar has many uses, not only to extract valuable substances, but also to make fertilizers and pottery. These applications show that eggshell is a very valuable resource, and we should make full use of this resource.