# The total hardness is always listed in parts-per-million (ppm) of CaCO3 (or mg CaCO3 /kg H2O)....

## Question:

The total hardness is always listed in parts-per-million (ppm) of {eq}CaCO_3 {/eq} (or {eq}mg CaCO_3 / kg H_2O {/eq}). Since the density of water is 1.0 g/mL, one ppm would be the same as the number of mg of CaCO3 per liter of water. Determine the number of moles of {eq}CaCO_3 {/eq} present in the titrated sample of water, assuming that all the {eq}Ca^{2+} {/eq} combines with {eq}CO_3^{2-} {/eq}? The titration of 25.00 mL took 19.290 mL of {eq}3.765x 10^{-3} {/eq} M EDTA solution to reach the endpoint.

## Hardness of Water:

The hardness of water arises due to the presence of minerals in the water. The minerals include sulfate, nitrate, and bicarbonate of calcium and magnesium ions. Hardness is classified into two categories:(1) Temporary hardness and (2) Permanent hardness.

## Answer and Explanation: 1

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Molarity of a solution is the ratio of the number of moles of solute to the volume of solution in Liter

Hence, the total number of mol of EDTA...

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