Question

If 100kg of a water sample contains 6 g of $MgS{O}_4$. The degree of hardness of the water sample is

• A. 6 ppm
• B. 60 ppm
• C. 5 ppm
• D. 50 ppm

Answer 1

The correct option is D

50 ppm

100 Kg (${10}^5$ g) of given water sample contains 6g of $MgS{O}_4$

Weight of $MgS{O}_4$ in ${10}^6$ g water =[$\frac{6}{{10}^5}$] x ${10}^6$ =60g

120g of $MgS{O}_4$ = 100g of $CaC{O}_3$

60g of $MgS{O}_4$ = [$\frac{60}{120}$] x $100$ = 50g of $CaC{O}_3$

$\therefore$ Degree of hardness due to $MgS{O}_4$ =50ppm