Question

Hardness of water is $200$ ppm. The normality of $CaC{O}_3$ in the water is in the form of $y\times 10^3$. Identify $y$.

Answer 1

Answer: 4

Hardness is weight in grams of $CaC{O}_3$ in $10^6$ mL of $H_{2}O$ $(\because d$ of $H_{2}O=1)$
or Hardness $=10^{6}g$ of $H_{2}O$
$MW\left(CaC{O}_3\right)=100g$ mol ${}^{-1}$
$M=\frac{W_2\times 1000}{MW\times \text{Vol. of solution in mL}}$
$=\frac{200\times 1000}{100\times 10^6}=2\times 10^{-3}M$
$N=v.f\times M$
$=2\times 2\times 10^{-3}$
$=4\times 10^{-3}N$