The hardness of a water sample containing expressed as equivalents (in ppm) is_____________.
(molar mass of is 120.37 g/mol)
100ppm
200ppm
99.85ppm
111.5ppm
We know that,
The hardness of Water :
The hardness of water is due to the presence of bicarbonates, chlorides, and sulfates of calcium and magnesium bicarbonates causes temporary hardness while chlorides and sulphates cause permanent hardness. The extent of hardness is called degree of hardness. It is defined as the number of parts by weight of calcium carbonate present In one million parts by weight of water that is, in ppm (milligrams per litre) of CaCO3
10–3 molar CaSO4 = 10–3 moles of CaSO4 present in 1 L solution.
We assume
nCaCO3 = nCaSO4
weight of CaCO3 / molar mass of CaCO3 = mole of CaSO4
weight of CaCO3 /100 = 10-3
weight of CaCO3 = 100 X 10-3
And the volume of water = 1 L then
weight of water = 1000
Hence, the option number (1) is correct.