Question

100 ml of water sample has a hardness equivalent to 12.5 ml of 0.08 N MgSO4. What is its

hardness in ppm?​

Answer 1

Answer:

Its hardness in ppm is 500 ppm.

Explanation:

A/Q,

No. of gram equivalent of MgSO4 = No. of gram equivalent of CaCO3.

⟹ No. of gram equivalent of CaCO3 = 0.02gm.

⟹ $\sf Mass \: of \: CaCO3 = \dfrac{0.002}{2} moles$

⟹ Moles of CaCO3 = 0.1gm

⟹ Mass = $\sf \dfrac{moles}{molar \: mass}$

⟹ Degree of Hardness = $\sf \dfrac{mass \: of \: CaCO3 \times 10^6}{mass \: of \: water}$

⟹ Degrees of Hardness = $\sf \dfrac{0.1 \times 10^6}{200}$

⟹ Degrees of Hardness = 500ppm

The degree of hardness in ppm is 500ppm.