What is meant by PCBs?
PCBs are polychlorinated biphenyls. They are contaminants of water. They are used as fluids in transformers and capacitors.
A person was using water supplied by Municipality. Due to shortage of water, he started using underground water. He felt laxative effect. What could be the cause?
Ozone is a toxic gas and is a strong oxidizing agent, even then its presence in the stratosphere is very important. Explain what would happen if ozone from this region is completely removed.
Assertion (A): Carbon dioxide is one of the important greenhouse gases. Reason (R): It is largely produced by respiratory function of animals and plants.
(a) Both A and R are true and R is the correct explanation of A.
(b) Both A and R are true but R is not the correct explanation of A.
(c) Both A and R are not correct.
(d) A is not correct but R is correct.
Biochemical Oxygen Demand, /BOD) is a measure of organic material present in water. BOD value less than 5 ppm indicates a water sample to be
Acid rain is known to contain some acids. Name these acids. From where do they come in rain?
A large number offish are suddenly found floating dead on a lake. There is no evidence of toxic dumping but you find an abundance of phytoplankton. Suggest a reason for the fish kill.
Match the pollutants given in Column I with their effects given in Column II.
(a) Sulphur dioxide causes classical smog, acid rain, water pollution, induces breathing problems, causes damage to buildings, corrosion of metals.
(b) Using carbamates as pesticides can cause nerve diseases in humans
(c) Using synthetic detergents for washing clothes causes water pollution.
(d) Unsaturated hydrocarbons and nitrogen oxides produced by automobiles and factories cause photochemical smog, damage to plant life, corrosion to building material, induce breathing problems, water pollution.
(e) Chlorofluorocarbons are believed to be the main reason for ozone layer depletion.
| Column I | Column II | ||
| (a) | Phosphate fertilizers in water | (1) | BOD level of water increases |
| (b) | Methane in air | (2) | Acid rain |
| (c) | Synthetic detergents in water | (3) | Global warming |
| (d) | Nitrogen oxides in air | (4) | Eutrophication |
Dissolved oxygen in water is v £ry important for aquatic life. What processes are responsible for the reduction of dissolved oxygen in water?
Assertion (A): Photochemical smog is oxidizing in nature.
Reason (R): Photochemical smog contains N02 and 03, which are formed during the sequence of reactions.
(a) Both A and R are true and R is the correct explanation of A.
(b) Both A and R are true but R is not the correct explanation of A.
(c) Both A and R are not correct.
(d) A is not correct but R is correct.
The acids present in acid rain are________ .
(a) Peroxyacetylnitrate
(b) H2C03
(c) HN03
(d) H2S04
Match the pollutant(s) in Column I with the effect(s) in Column II.
| Column I | Column 11 | ||
| (a) | Oxides of sulphur | (1) | Global warming . |
| (b) | Nitrogen dioxide , | (2) | Damage to kidney |
| (c) | Carbon dioxide | (3) | ‘Blue baby' syndrome |
| (d) | Nitrate in drinking water | (4) | Respiratory diseases |
| (e) | Lead | (5) | Red haze in traffic and congested areas |
Sometime ago formation of polar stratospheric clouds was reported over Antarctica. Why were these formed? What happens when such clouds break up by warmth of sunlight?
(a) Define eutrophication and pneumoconiosis.
(b) Write difference between photochemical and classical smog.
Match the terms given in Column I with the compounds given in Column
| Column 1 | Column II | ||
| (a) | Acid rain | (1) | CHC12-CHF2 |
| (b) | Photochemical smog | (2) | CO |
| (c) | Combination with haemoglobin | (3) | co2 |
| (d) | Depletion of ozone layer | (4) | so2 |
| (5) | Unsaturated hydrocarbons | ||
Dinitrogen and dioxygen are main constituents of air but these do not react with each other to form oxides of nitrogen because____________ .
(a) the reaction is endothermic and requires very high temperature.
(b) the reaction can be initiated only in presence of a catalyst.
(c) oxides of nitrogen are unstable.
(d) N2 and 02 are unreactive,
Assertion (A): Greenhouse effect was observed in houses used to grow plants and these are made of green glass.
Reason (R): Greenhouse name has been given because glass houses are made of green glass.
(a) Both A and R are true and R is the correct explanation of A.
(b) Both A and R are true but R is not the correct explanation of A.
(c) Both A and R are not correct.
(d) A is not correct but R is correct.
For your agricultural field or garden you have developed a compost producing pit. Discuss the process in the light of bad odour, flies and recycling of wastes for a good produce.
What do you mean by greenhouse effect? What is the role of CO2 in the greenhouse effect?
Which of the following conditions shows the polluted environment?
(a) pH of rain water is 5.6.
(b) Amount of carbon dioxide in the atmosphere is 0.03%.
(c) Biochemical oxygen demand is 10 ppm.
(d) Eutrophication
On the basis of chemical reactions involved, explain how do chlorofluoro- carbons cause thinning of ozone layer in stratosphere.