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SSC MTS 2019 PYQ — Question 45

SSC MTS Previous Year - 06 August 2019 - Shift 3 • General Awareness • Q45

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Which of the following ions are responsible for hardness of water?

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Correct answer: B

Explanation

Correct Answer is option 2 i.e. Calcium and Magnesium ions

Hardness of water:
  • The simple definition of water hardness is the amount of dissolved calcium and magnesium in the water.
  • Hardness is most commonly expressed as milligrams of calcium carbonate equivalent per litre.
  • Water containing calcium carbonate at concentrations below 60 mg/l is generally considered as soft; 60–120 mg/l, moderately hard; 120–180 mg/l, hard; and more than 180 mg/l, very hard.