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

$A$ water sample has $ppm$ level concentration of the following metals: $Fe = 0.2$,$Mn = 0.05$,$Cu = 3.0$,$Zn = 5.0$. The metal that makes the water sample unsuitable for drinking is

Identify the incorrect statement.

Some statements are given:
$(S_1) \ CO_2$ is a greenhouse gas.
$(S_2)$ Classical smog contains smoke,fog,and a high concentration of $SO_2$.
$(S_3) \ DDT$ is biodegradable.
$(S_4)$ Drinking water should have a high $B.O.D.$
Which is the correct sequence of true $(T)$ or false $(F)$ regarding the above statements?

Aldehydes are produced in the atmosphere by:

Methemoglobinemia is due to