JEE Main20198 Apr 2019Morning ShiftChemistryHydrogenActual
100 m L 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 C a C O 3 is: (molar mass of calcium bicarbonate is 162 g m m o l - 1 and magnesium bicarbonate is 146 g m o l - 1 )
Options
- A100 p p m
- B1,000 p p m
- C5,000 p p m
- D10,000 p p m
Correct answer
D. 10,000 p p m
Step-by-step solution
n e q C a C O 3 = n e q C a H C O 3 2 + n e q M g H C O 3 2 or, W 100 × 2 = 0.81 162 × 2 + 0.73 146 × 2 ∴ W = 1.0 ∴ Hardness = 1.0 100 × 10 6 = 10000   p p m