Question

One litre hard water contains $1$ mg $CaC{l}_2$ and $1$ mg $MgS{O}_4$. The hardness of water is:

• A. $1.743$ ppm
• B. $1.745$ ppm
• C. $1.734$ ppm
• D. none of the above

Answer 1

The correct option is C $1.734$ ppm

Given that, One litre hard water contains $1$ mg $CaC{l}_2$ and $1$ mg $MgS{O}_4$.
The hardness of water is $\frac{(\frac{1}{111}+\frac{1}{120})+{10}^{-3}\times 100}{1000}\times {10}^6=1.734$ ppm.