Alum’s capacity to purify water is due to
1.softens hard water
2.pathogenic bacteria get destroyed
3. impurities’ coagulation
4. it improves taste
Posted Date:-2021-03-08 07:12:34
The coldest region of the atmosphere
1.Troposphere
2.Thermosphere
3.Stratosphere
4.Mesosphere
Posted Date:-2021-03-08 07:12:34
Depletion of the ozone layer is caused due to
1.Ferrocene
2.Fullerenes
3. Freons
4.Polyhalogens
Posted Date:-2021-03-08 07:12:34
Find the incorrect statement
1. BOD value of clean water is less than 5 ppm
2. Drinking water pH should be between 5.5-9.5
3.carbon, sulphur and nitrogen oxides are the most widespread air pollutants
4.dissolved oxygen concentration below 5 ppm is ideal for the growth of fish
Posted Date:-2021-03-08 07:12:34
Find the secondary pollutant among these
1.PAN
2.N2O
3.SO2
4.CO2
Posted Date:-2021-03-08 07:12:34
Photochemical smog normally does not contain
1. Chlorofluorocarbons
2.Peroxyacetyl nitrate
3. Ozone
4.Acrolein
Posted Date:-2021-03-08 07:12:34
In the air, N2 and O2 occur naturally but they do not react to form oxides of nitrogen because
1.oxides of nitrogen are unstable
2.catalyst is required for the reaction
3. the reaction is endothermic
4.N2 and O2 do not react with each other
Posted Date:-2021-03-08 07:12:34
The compound essential for the process of photosynthesis has this element
1. Ca
2.Ba
3. Fe
4.Mg
Posted Date:-2021-03-08 07:12:34
The reaction responsible for the radiant energy of the Sun is
1.nuclear fission
2.nuclear fusion
3. chemical reaction
4.combustion
Posted Date:-2021-03-08 07:12:34
Which of the oxide of nitrogen is not a common pollutant?
1. N2O5
2. N2O
3.NO
4.NO2
Posted Date:-2021-03-08 07:12:34