Question

100 ml of water sample with initial pH 7.5 is titrated to pH=4.5 using 15 ml of 0.02 N $H_{2}S{O}_4$. The total alkalinity of water (in $\frac{mg}{l}$ as $CaC{O}_3$). Rounded off to nearest integer is

• A. 150

Answer 1

The correct option is A 150
$\because$ 1 ml of 0.2 N $H_{2}S{O}_4$ consumes 1 mg of alkalinity as $CaC{O}_3$

$\because$ Total alkalinity in 100 ml of water = 15 mg as $CaC{O}_3$
$\because$ Alkalinity in $\frac{mg}{l}$ as $CaC{O}_3=\frac{15}{100\times {10}^{-3}}\frac{mg}{l}asCaC{O}_3=150\frac{mg}{l}asCaC{O}_3$