Question

The total concentration of Ca2+ and Mg2+ in a sample of hard water was determined by titrating a 0.375 L sample of the water with a solution of EDTA4-. The EDTA chelates the Ca2+ and Mg2+.

a. Forming a precipitate
b. Changing color
c. Reducing pH
d. Producing gas

Answer 1

When titrating hard water with EDTA4-, the chelation of Ca2+ and Mg2+ ions occurs, forming stable ring complexes and preventing them from interacting with other substances. The reaction does not produce a precipitate, change in color, pH reduction, or gas production.

Step-by-step explanation:

When titrating hard water with a solution of EDTA4-, the chelation of Ca2+ and Mg2+ ions occurs. This means that the EDTA forms a stable ring complex with these metal cations, preventing them from interacting with other substances in the solution. The chelation reaction does not result in a precipitate. Instead, it forms a complex that does not produce any visible changes such as color change, pH reduction, or gas production.