$A$ water sample has $ppm$ level concentration of following anions: $F^{-} = 10 \ ppm$,$SO_4^{2-} = 100 \ ppm$,$NO_3^{-} = 50 \ ppm$. The anion/anions that make the water sample unsuitable for drinking is/are:

How many ozone molecules are destroyed by a single chlorine free radical?

Global warming may result in

Provide the correct statement for the following: (Use $T$ for True and $F$ for False statements.) $(1)$ Plants obtain elements like carbon,hydrogen,and oxygen from air and water. $(2)$ Plants obtain elements like $N, P, K, Ca$ from the soil. $(3)$ Compound fertilizers contain nitrogen as ammonium nitrate,phosphorus as $PCl_3$,and potassium as $KO_2$. $(4)$ The use of $NPK$ fertilizers increases the production of crops and vegetables in the soil.

Acid rain is mainly caused by the emissions of which of the following gases?
$I.$ Sulphur dioxide
$II.$ Carbon dioxide
$III.$ Nitrogen dioxide
$IV.$ Methane

Indiscriminate use of $DDT$ is undesirable because