Question

The amount of calcium carbonate in line stone is determined by which of the following tests?
1. Acid test
2. Ball test
3. Heat test
4. Compressive strength test

Answer 1

Correct Answer - Option 1 : Acid test

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.