Question

100 mL of a water sample contains 0.81 g of calcium bicarbonate and 0.73 g of magnesium bicarbonate. The hardness of this water sample expressed in terms of equivalents of CaCO₃
is:
(molar mass of calcium bicarbonate is 162 gmol⁻¹
and magnesium bicarbonate is 146 gmol⁻¹)
(A) 10, 000 ppm (B) 1, 000 ppm
(C) 5,000 ppm (D) 100 ppm

Answer 1

Answer:

(A) 10,000 ppm correct answer

Thanks for the question..

Answer 2

The  hardness of this water sample expressed in terms of equivalents of CaCO₃  is 1000 ppm.

Explanation:

neq = CaCO3 = neq = Ca(HCO3)2 + neq Mg (HCO3)

Or

W / 100 x 2 = 0.81 / 162 x 2 + 0.73 / 146 x  2

w = 0.1

Hardness = 1.0 / 100 x 10^6 = 1000 ppm

Thus the  hardness of this water sample expressed in terms of equivalents of CaCO₃  is 1000 ppm.