Question

Hardness of water is $200\, ppm.$ Calculate the molarity and normality of $CaCO _{3}$ of the water

• A. $4 \times 10^{-3} M ; 2 \times 10^{-3} N$
• B. $2 \times 10^{-6} M ; 4 \times 10^{-3} N$
• C. $2 \times 10^{-3} M ; 4 \times 10^{-3} N$
• D. $1 \times 10^{-3} M ; 4 \times 10^{-3} N$

Answer 1

Answer: (C)

$200\, ppm$ mean $200\, g$ in $10^{6}\, mL$ solution

Molarity $=\frac{w t}{M \cdot w} \times \frac{1000}{V_{ mL }}=\frac{200}{100} \times \frac{1000}{10^{6}}$

$=2 \times 10^{-3}\, M$

Normality $=\frac{200}{50} \times \frac{1000}{10^{6}}$

$=4 \times 10^{-3}\, N$