Question

Q7 A water sample gave following constituents on analysis in mg/L. Ca(HCO3)2 = 81ppm, CaSO4
68ppm, MgSO4 = 12ppm, MgCl2 = 95ppm, Mg(HCO3)2 73ppm and NaCl = 4.8ppm.Calculate
the cost of chemicals required for softening 20000 litres of water, if the purity of lime is 95% and
that of soda is 90%. The cost of 100kg each of Time and soda are Rs 75 and Rs 2840 respectively.

Answer 1

What is you need me to answer I can’t understand

Answer 2

Answer:

We can calculate the hardness of given water sample as:

(i) Ca(HCO

3

)

2

CaCO3≡CaCO

3

162ppm≡100ppm

∴81ppm≡50ppm

(ii) Mg(HCO

3

)

2

≡CaCO

3

146 ppm ≡ 100 ppm

∴73ppm≡50ppm

(iii) CaSO

4

≡CaCO

3

136ppm≡100ppm

∴68ppm≡50ppm

(iv) MgSO

4

≡CaCO

3

120ppm≡100ppm

∴60ppm≡50ppm

Total degree of hardness of water =50×4=200ppm