A water sample has ppm level concentration of following anions
`F^(-)=10 , SO_(4)^(2-)=100 , NO_(3)^(-) =50`
the anion/anions that make/makes the water sample unsuitable for drinking is/are

Options

A. only `NO_3^(-)`
B. both `SO_4^(2-) and NO_(3)^(2-)`
C. only `F^(-)`
D. only `SO_4^(2-)`

Answer

C

Explanation

The `F^(-)` ion concentration is above the permissible limit in drinking water. Therefore, it is unsuitable for drinking. Excess concentration of `F^(-)` ions (greater than 2ppm ) causes brown mottling of teeth enamel.