The hardness of a water sample containing 10- 3M MgSO4 expressed as CaCO3 equivalents (in ppm) is (molar mass of MgSO4 is 120.38 g / m o l and molar mass of CaCO3 is 100.08 g / m o l )

Question

The hardness of a water sample containing 10- 3M MgSO4 expressed as CaCO3 equivalents (in ppm) is (molar mass of MgSO4 is 120.38 g / m o l and molar mass of CaCO3 is 100.08 g / m o l ) (A) 50 (B) 75 (C) 90 (D) 100

Tardigrade Admin · Accepted Answer

Given: 10- 3M MgSO4 i.e. 10- 3 mole MgSO4 present in 1 litre solution nM g S O4=nC a C O3 Mass of CaCO3=10- 3× 100 ppm (in terms of CaCO3 ) =(m a s s o f C a C O3 /w e i g h t o f so l u t i o n)× 106 ppm (in terms of CaCO3 ) =(1 0- 3 × 100/1000)× 106=100 ppm

Q. The hardness of a water sample containing 10−3MMgSO4​ expressed as CaCO3​ equivalents (in ppm) is (molar mass of MgSO4​ is 120.38 g/mol and molar mass of CaCO3​ is 100.08 g/mol )

50

75

90

100

Given: 10−3MMgSO4​ i.e. 10−3 mole MgSO4​ present in 1 litre solution nMgSO4​​=nCaCO3​​ Mass of CaCO3​=10−3×100 ppm (in terms of CaCO3​ ) =weightofsolutionmassofCaCO3​​×106 ppm (in terms of CaCO3​ ) =100010−3×100​×106=100ppm

Q. The hardness of a water sample containing $1 0^{- 3} M M g S O_{4}$ expressed as $C a C O_{3}$ equivalents (in ppm) is

(molar mass of $M g S O_{4}$ is 120.38 $g / m o l$ and molar mass of $C a C O_{3}$ is 100.08 $g / m o l$ )