BACK TITRATION- DETERMINATION OF THE CARBONATE CONTENT IN GARDEN LIME NAME: OSEI BONSU ERIC ID: 3906409 EXPERIMENT: I.2.2.1. DEMONSTRATOR: BONEYFACE ANTWI DATE: 8TH FEBRAURY 2011. AIM
To determine the carbonate content of garden lime, by performing an analysis involving a back titration. INTRODUCTION
Garden lime is used by gardeners to reduce the acidity of the soil. It consists of ground limestone which is predominantly calcium carbonate. Different soil types behave differently hence there is the need to test for acidity. To raise the pH and lower the acidity or sweeten the soil, lime is added. Agricultural lime or garden lime is made from pulverized limestone or chalk. Some types of garden lime are dolomite lime, quicklime and slaked lime. Calcium carbonate occurs in nature as limestone in various forms, such as marble, chalk and coral. It is produced either as powdered or precipitated calcium carbonate. Calcium carbonate decomposes to calcium oxide and CO2 on heating. Treatment with dilute mineral acids produces corresponding calcium salts with liberation of CO2: CaCO3 + 2HNO3 Ca(NO3)2 + H2O + CO2(g) In this experiment, the mineral acid is added in excess to the calcium carbonate and the excess titrated against standard sodium hydroxide. This kind of titration is termed back titration. In this procedure, the analyte is consumed using excess titrant and the end point is...
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