A water sample has ppm level concentration of following anions $\mathrm{F}^{-}=10 ; \quad \mathrm{SO}_{4}^{2-}=100 ; \quad \mathrm{NO}_{3}^{-}=50$ The anion/anions that make/makes the water sample unsuitable for drinking is/ are :

(B) both $\mathrm{SO}_{4}^{2-}$ and $\mathrm{NO}_{3}^{-}$

(D) only $\mathrm{SO}_{4}^{2-}$

JEE Main · 2017 · 02 Apr 2017 · Offline · Environmental Chemistry

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 :

Answer: (C)

Set each anion beside its drinking-water limit: fluoride about

1

ppm, sulphate about

500

ppm, nitrate about

50

ppm. The sample's sulphate at

100

and nitrate at

50

sit within limit, but its fluoride at

10

ppm is ten times the safe level, enough to cause fluorosis. Only the fluoride makes this water unfit to drink.

JEE Main · 2017 · 02 Apr 2017 · Offline · Single correct option