Question

How many liters of hard water may contain 60 mg of $MgS{O}_4$ in order to have a degree of hardness of 25 ppm?

Answer 1

Hardness (in ppm) = $\frac{WeightofMgS{O}_4\left(inmg\right)}{Volumeofwater\left(inL\right)}$

$\therefore$ $25=\frac{60}{Volume}$

$\therefore$ $Volume=2.4$ litres.

$\therefore$ $2.4$ litres of hard water contains $60$ mg of $MgS{o}_4$ to have degree of hardness $25$ ppm.