Why does water covered with excessive algal growth become polluted?
Presence of excessive algal growth shows that water contains a lot of phosphate due to inflow of fertilizers, etc from the surroundings. Hence, such a sample of water is polluted.
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.
Oxidation of sulphur trioxide in the absence of a catalyst is a slow process but this oxidation occurs easily in the atmosphere. Explain how does this happen. Give chemical reactions for the conversion of S02 into S03.
Assertion (A): The pH of acid rain is less than 5.6.
Reason (R): Carbon dioxide present in the atmosphere dissolves in rain water and forms carbonic acid.
(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.
What would have happened if the greenhouse gases were totally missing in the earth’s atmosphere? Discuss.
Match the activity given in Column I with the type of pollution created by it given in Column II.
| Column I | Column II | |||
| Releasing gases to the atmosphere after burning waste material containing Sulphur. | 0) | Water pollution | ||
| Using carbamates as pesticides. | (2) | Photochemical smog, damage to plant life, corrosion to building material, induce breathing problems, water pollution | ||
| Using synthetic detergents for washing clothes. | (3) | Damaging ozone layer | ||
| Releasing gases produced by automobiles and factories in the atmosphere. | (4) | May cause nerve diseases in human . | ||
| Using chlorofluorocarbon compounds for cleaning computer parts. | (5) | Classical smog, acid rain, water pollution, induce breathing problems, damage to buildings, corrosion of metals | ||
Acid rain is known to contain some acids. Name these acids. From where do they come in rain?
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?
What do you mean by green chemistry? How will it help in decreasing environmental pollution ?
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.
On the basis of chemical reactions involved, explain how do chlorofluoro- carbons cause thinning of ozone layer in stratosphere.
What could be the harmful effects of improper management of industrial and domestic solid waste in a city?
A factory was started near a village. Suddenly villagers started feeling the presence of irritating vapours in the village and cases of headache, chest pain, cough, dryness of throat and breathing problems increased. Villagers blamed the emissions from the chimney of the factory for such problems. Explain what could have happened. Give chemical reactions for the support of your explanation.
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 | ||
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
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,
During an educational trip, a student of Botany saw a beautiful lake in a , village. She collected many plants from that area. She noticed that villagers were washing clothes around the lake and at some places, waste material from houses was destroying its beauty. After few years, she visited the same r lake again. She was surprised to find that the lake was covered with algae, stinking smell was coming out and its water had become unusable. Can you explain the reason for this condition of the lake?
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?
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.
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.
Assertion (A): Excessive use of chlorinated synthetic pesticides causes soil and water pollution.
Reason (R): Such pesticides are non-biodegradable.
(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.
Assertion (A): If BOD level of water in a reservoir is less than 5 ppm it is highly polluted.
Reason (R): High biological oxygen demand means low activity of bacteria in water.
(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.