In an EDTA experiment, the following values are obtained. Calculate the different types of hardness. (EDTA =0.01M) i) 50 ml hard water sample = 25 ml EDTA ii) 50 ml boiled water sample = 14 ml EDTA

To calculate the different types of hardness, we need to understand that the hardness of water is due to the presence of multivalent metallic ions, primarily calcium and magnesium ions. The hardness is usually expressed in terms of equivalent amount of CaCO3 because it is the most common source of hardness.

The formula to calculate hardness is:

Hardness (mg/L or ppm) = (Volume of EDTA * Molarity of EDTA * Equivalent weight of CaCO3 * 1000) / Volume of water sample

The equivalent weight of CaCO3 is 50.

1. Total hardness:

Total hardness is calculated using the hard water sample.

= (25 ml * 0.01 mol/L * 50 g/mol * 1000) / 50 ml = 250 mg/L or ppm

2. Permanent hardness:

Permanent hardness is calculated using the boiled water sample. Boiling the water removes temporary hardness, so what's left is the permanent hardness.

= (14 ml * 0.01 mol/L * 50 g/mol * 1000) / 50 ml = 140 mg/L or ppm

3. Temporary hardness:

Temporary hardness is the difference between total hardness and permanent hardness.

= Total hardness - Permanent hardness = 250 mg/L - 140 mg/L = 110 mg/L or ppm

So, the total hardness is 250 mg/L, the permanent hardness is 140 mg/L, and the temporary hardness is 110 mg/L.