Green chemistry means such reactions that:

1.	Produce colour during reactions
2.	Reduce the use and production of hazardous chemicals.
3.	Are related to the depletion of the ozone layer.
4.	Study the reactions in plants.

A gas that is not common component of photochemical smog is-

1. Ozone

2. Acrolein

3. Peroxyacetyl nitrate

4. Chlorofluorocarbons

Which one of the following statements regarding photochemical smog is not correct?

1. Carbon monoxide does not play any role in photochemical smog formation

2. Photochemical smog is an oxidising agent in character

3. Photochemical smog is formed through photochemical reaction involving energy

4. Photochemical smog does not cause irritation in eyes and throat

Which one of the following statements is not true?

1. Concentration of DO below 6 ppm is good for the growth of fish

2. Clean water would have a BOD value of less than 5 ppm

3. Oxides of sulphur, nitrogen and carbon arc the most widespread air pollutant

4. pH of drinking water should be between 6.5-8.5