Question

Which one of the following processes will produce hard water ?

• A. Saturation of water with $MgC{O}_3$
• B. Saturation of water with $CaS{O}_4$
• C. Addition of $N{a}_{2}S{O}_4$ to water
• D. Saturation of water with $CaC{O}_3$

Answer 1

The correct option is B Saturation of water with $CaS{O}_4$

Permanent hardness of water is due to chlorides and sulphates of calcium and magnesium i.e. $CaC{l}_2,CaS{O}_4,MgC{l}_2$ and $MgS{O}_4$.