The reaction between CaCO3 and CH3COOH is not a double displacement reaction. A double displacement reaction involves the exchange of ions between two compounds, resulting in the formation of two new compounds. In the reaction between CaCO3 and CH3COOH, there is no exchange of ions and thus, it is not a double displacement reaction.

The reaction between CaCO3 and CH3COOH is an acid-base reaction, in which CH3COOH (acetic acid) acts as an acid and CaCO3 (calcium carbonate) acts as a base. The reaction can be represented as follows:

CaCO3 + 2CH3COOH → Ca(CH3COO)2 + H2O + CO2

In this reaction, CaCO3 reacts with CH3COOH to form calcium acetate [Ca(CH3COO)2], water (H2O), and carbon dioxide (CO2).