Answer to Question #171736 in Physical Chemistry for Akshat

Question

Calculate the amount of lime and soda (assuming that they are 100% pure) for the treatment of 1,00,000 L of water, whose analysis report is as follows: Ca(HCO3)2 = 15.3 ppm, Mg(HCO3)2 = 19 ppm, CaSO4 = 24.6 ppm, CaCl2 = 27.75 ppm, MgSO4 = 35 ppm, MgCl2 = 25 ppm, NaAlO2 = 16 ppm, Fe2O3 = 3.3 ppm, KNO3 = 3 ppm, NaCl = 10 ppm. Also, calculate the temporary and permanent hardness of the water sample in terms of CaCO3 equiv

Answer 1

1 mole of calcium oxide corresponds to 2 moles of calcium carbonate.

The molar mass of calcium oxide and calcium carbonate are 56 g/mol and 100 g/mol respectively.

0.56 g (0.01 mole) of lime will correspond to 2 g (0.02 mole) of calcium carbonate.

Now, 10 L of water corresponds to 10000 ml.

Hence, 2 g calcium carbonate in 10000 ml of water corresponds to 200 ppm.