EQUIPMENT

1. pH Meter
2. 50 mL Burette
3. Hot Plate

REAGENTS

1. 2.0N HCl
2. 0.25 N NaOH

PROCEDURE

1. Weigh 1.00 g of sample into a 150 mL beaker.
2. Add 12 mL of 2.0N HCl.
3. Add 38 mL Deionized water.
4. Boil gently for 5 minutes and let cool.
5. Immerse pH combination electrode in the solution.
6. Titrate to pH 8.30 with 0.25N NaOH.

CALCULATION

% Calcium Carbonate Equivalent = [ 24 - (mL NaOH × .25) ] × 5

REFERENCE

1. Horwitz, W. (Ed), 1980, Official Methods of Analysis of the Association of Official Analytical Chemists, 16th Edition, Washington, D. C., P 1.