100 mL sample of hard water is titrated with 500 " mL of " 0.001 M EDTA solution at `pH=10`, using eriochrome black-T indicator to reach equivalence point. An equal another amount of hard water sample is boiled for 30 min. After filtration and cooling, the same sample is titrated with 200 " mL of " 0.011 M EDTA solution at `pH=10` using Mg-EDTA complex solution and erichrome black-T indicator to reach equivalence point.
(i). Calculate the total hardness of water sample (temporary`+`permanent) in ppm of `CaCO_3`.

Explanation

To calculate the total hardness of the water sample in ppm of CaCO₃, we will follow these steps:

### Step 1: Calculate the moles of EDTA used in the first titration
Given:
- Volume of EDTA solution = 500 mL = 0.500 L
- Molarity of EDTA solution = 0.001 M

Using the formula:
...