Assertion and Reason Questions for Class 11 Chemistry Chapter 14 Environmental Chemistry
Directions:
(a) Assertion is correct, reason is correct; reason is a correct explanation for assertion.
(b) Assertion is correct, reason is correct; reason is not a correct explanation for assertion
(c) Assertion is correct, reason is incorrect
(d) Assertion is incorrect, reason is correct.
Q.1. Assertion: The pH of acid rain is less than 5.6.
Reason: Carbon dioxide present in the atmosphere dissolves in rain water and forms carbonic acid.
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Answer: (b)Q.2. Assertion: Carbon dioxide is one of the important greenhouse gases.
Reason: It is largely produced by respiratory function of animals and plants.
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Answer: (b)Q.3. Assertion: Ozone is destroyed by solar radiation in upper stratosphere.
Reason: Thinning of the ozone layer allows excessive UV radiations to reach the surface of earth.
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Answer: (d)Q.4. Assertion: Excessive use of chlorinated synthetic pesticides causes soil and water pollution.
Reason: Such pesticides are non-biodegradables.
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Answer: (a)Q.5. Assertion: Photochemical smog is oxidising in nature.
Reason: Photochemical smog contains NO2 and O3, which are formed during the sequence of reactions.
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Answer: (a)Q.6. Assertion: Suspended particulate matter (SPM) is an important pollutant released by diesel vehicles.
Reason: Catalytic converters greatly reduce pollution caused by automobiles.
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Answer: (b)Q.7. Assertion: Dinitrogen and dioxygen do not react with each other at a normal temperature.
Reason: At high altitudes dinitrogen combines with dioxygen to form oxides of nitrogen
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Answer: (b)Q.8. Assertion: If BOD level of water in a reservoir is less than 5 ppm it is highly polluted.
Reason: High biological oxygen demand means low activity of bacteria in water.
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Answer: (c)Q.9. Assertion: Uncatalysed oxidation of sulphur dioxide is a slow process.
Reason: Particulate matter in polluted air catalyses the oxidation of sulphur dioxide.
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Answer: (a)Q.10. Assertion: CO2 causes green house effect.
Reason: Other gases do not show such effect.
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Answer: (c)Q.11. Assertion: Eutrophication shows increase in productivity in water.
Reason: With increasing eutrophication, the diversity of the phytoplankton increases.
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Answer: (b)Q.12. Assertion: Green house effect was observed in houses used to grow plants and these are made of green glass.
Reason: Green house name has been given because glass houses are made of green glass.
