Engineering Chemistry

3

Estimation of Copper by EDTA Method

AIM

To estimate the amount of copper present in 100 ml of the given solution using approximately 0.01 M ethylenediamine tetraacetic acid (EDTA) solution.

PRINCIPLE

The estimation is based on complexometric titration. Copper ions in ammonia solution form a blue colour complex with Fast Sulphon Black-F (FSB-F) indicator. EDTA reacts with the copper ions and releases the free indicator; hence, the colour of the solution changes from blue to dark green.

Cu²+ + FSB-F → Cu – FSB-F (unstable blue colour complex)

Cu – FSB-F + EDTA → Cu – EDTA + FSB-F

(stable dark green colour complex)

PROCEDURE

Part A: Preparation of standard copper sulphate solution

Take approximately 0.25 g of copper sulphate crystals in a ...