Question

Hardness of water is estimated by simple titration with which compound?

• A. ${\text{Na}}_2\text{(EDTA)}$
• B. $\text{Fe(EDTA)}$
• C. $\text{Mg(EDTA)}$
• D. $\text{Co(EDTA)}$

Answer 1

The correct option is A ${\text{Na}}_2\text{(EDTA)}$

The ${\text{Ca}}^{2+}{\text{and Mg}}^{2+}$ ions from stable complexes with $EDTA$, and the difference in the stability constants of Ca and Mg complexes helps in the estimation of hardness of water.