Explanation: The amount of Calcium Carbonate in limestone is determined by performing the acid test. The acid used is dilute Hydrochloric acid. The reaction involved is: CaCO3+2‌HCl→CaCl2+H2O+CO2 The method used for measuring CaCO3 comprises the following steps 1. Dissolving limestone in hydrochloric acid. 2. Adding KOH solution and Calcium Carboxylate indicator into said solution. 3. Titrating the solution until its color turns to blue from red using EDTA standard solution and then working out the CaCO3 content on the basis of the titer of EDTA.