Water is said to have one degree of hardness when its soap destroying power is equivalent to the effect of _______ of calcium carbonate in one litre of water
- A1 mg
- B10 mg
- C14.25 mgCorrect
- D17.15 mg
Solution
Concept
Hardness is expressed as mg/L of CaCO3. One degree of hardness is defined by an equivalent CaCO3 amount per litre.
Explanation
Hardness (mg/L as CaCO3) = Σ (ion concentration × 50 / equivalent weight)
Correct answer: C) 14.25 mg