JEE Main 2023 — Environmental Chemistry Question with Solution

Fluoride ($F^{-}$) : High concentration of fluoride can lead to a condition known as fluorosis, affecting teeth and bones. Hence, the WHO sets the upper limit for fluoride in drinking water to be 1.5 ppm. This can be approximated to less than 2 ppm. Therefore, $F^{-}$ (List I: A) corresponds to < 2 ppm (List II: III).

Sulfate ($S{O}_4^{2-}$) : The standard concentration limit for sulphates in drinking water, according to WHO, is 500 ppm. Hence, $S{O}_4^{2-}$ (List I: B) matches with < 500 ppm (List II: IV).

Nitrate ($N{O}_3^{-}$) : An excess of nitrate in drinking water can lead to health conditions such as methemoglobinemia. The safe limit, according to the WHO, is 50 ppm. Hence, $N{O}_3^{-}$ (List I: C) corresponds to < 50 ppm (List II: I).

Zinc (Zn) : Zinc is an essential nutrient, but excessive amounts in drinking water can be harmful. The standard limit for zinc in drinking water is 5 ppm. So, Zn (List I: D) corresponds to < 5 ppm (List II: II).