NEET Chemistry The s-Block Elements Questions Solved


A water sample containing 6 mg of MgSO4/ litre has hardness in ppm equal to

(A) 10                                                             

(B) 5

(C) 6                                                               

(D) 3

(B). One litre of water contains 0.006 g MgSO4.

0.006 g MgSO4=0.00624+32+642

=0.006120/2 equivalent CaCO3

0.006 g MgSO4 = 0.00660×1002g CaCO3 = 0.005 g CaCO3

From 1 litre or 103g of water, 0.005 g CaCO3 is precipitated.

From 1 106g water. 0.005×106103=5g CaCO3 is precipitated.

Hardness of water = 5ppm.

Difficulty Level:

  • 20%
  • 35%
  • 36%
  • 11%
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