Environmental chemistry

Which one of the following statements is NOT correct?

Given below are two statements:
Statement I: Chlorofluoro carbons breakdown by radiation in the visible energy region and release chlorine gas in the atmosphere which then reacts with stratospheric ozone.
Statement II: Atmospheric ozone reacts with nitric oxide to give nitrogen and oxygen gases, which add to the atmosphere.
For the above statements choose the correct answer from the options given below:

The gas released during anaerobic degradation of vegetation may lead to:

Given below are two statements:

Statement I : The value of the parameter “Biochemical Oxygen Demand (BOD)” is important for survival of aquatic life.

Statement II : The optimum value of BOD is 6.5 ppm.

In the light of the above statements, choose the most appropriate answer from the options given below:

Given below are two statements:

Statement I : The pH of rain water is normally $\sim 5.6$

Statement II : If the pH of rain water drops below 5.6, it is called acid rain.

In the light of the above statements, choose the correct answer from the options given below

Given below are two statements:                                        

Statement I : An allotrope of oxygen is an important intermediate in the formation of reducing smog.

Statement II : Gases such as oxides of nitrogen and sulphur present in troposphere contribute to the formation of photochemical smog.

In the light of the above statements, choose the correct answer from the options given below:

Water sample is called cleanest on the basis of which one of the BOD values given below:

The measured BOD values for four different water sample (A-D) are as follows

A = 3 ppm;                           B = 18 ppm:                      C = 21 ppm;        D = 4 ppm.

The water samples which can be called as highly polluted with organic wastes, are

The water having more dissolved O₂ is:

Green chemistry in day-to day life is in the use of: