Question

In an experiment for determining water hardness, 75.00 ml of a water sample required 13.03 ml of an EDTA solution that is 0.009242 M. What is the ppm CaCO3 in this sample?

Could someone please tell me if this is correct?

Total hardness, ppm CaCO3 = mg CaCO3 / L

= 13.03 ml x 1.00 mg CaCO3/ml EDTA x 1000 ml/L
75 ml

= 173.733 mg CaCO3/L

= 173.7 ppm

Thanks for your help.

Answer 1

I don't know where you obtained 1 mg CaCO3/mL.
0.01303 x 0.009242M = ? mols CaCO3.
?mols CaCO3 x molar mass CaCO3 = grams CaCO3and that's in 75 mL. Convert to mg/L for ppm. Something like 160 ppm?