Question

The hardness of water caused by $0.25$ moles of $MgC{l}_2$ is equal to :

I) the hardness of water caused by $25$ grams of $CaC{O}_3$.

II) the hardness of water caused by $0.25$ moles of $CaC{O}_3$.

III) the hardness of water caused by $1$ moles of $CaC{O}_3$.

• A. only II is correct.
• B. I and II are correct.
• C. I and III are correct.
• D. only I is correct.

Answer 1

The correct option is B I and II are correct.

The hardness caused by $0.25$ moles of ${Mg}^{+2}$ will be same as the hardness caused by the $0.25$ moles of of ${Ca}^{+2}$.

$0.25$moles of $C{a}^{+2}$ $=$ $25$ grams of $CaC{O}_3$(25/100=0.25)

So I and II are correct.