The non-carbonate hardness of the sample in mg/l as CaCO3

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Direction: A water sample contains the following dissolved ions.
[Na⁺] = 56 mg/l; [Ca²⁺]
[Ca²⁺] = 40 mg/l; [Mg²⁺]
[Mg²⁺] = 30 mg/l; [Al³⁺]
[Al³⁺] = 3 mg/l; [HCO₃]
[HCO₃] = 190 mg/l; [Cl^-]
[Cl^-] = 165 mg/l; Water pH is 7.
Atomic weights: Ca: 40, Mg: 24, Al: 27, H: 1, C: 12, O: 16, Na: 23, Cl: 35.5.

The non-carbonate hardness of the sample in mg/l as CaCO₃ is

1. 225
2. 156
3. 86
4. 0

Correct Option: B

Non-carbonate hardness = Concentration of HCO^-₃ ×	Eq. wt of CaCO₃
	Eq. wt of HCO^-₃

= 190 ×	50	= 155.7 mg/l ≈ 156 mg/l.
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