CBSE Class 11 Chemistry – MCQ and Online Tests – Unit 14 – Environmental Chemistry
Every year CBSE schools conducts Annual Assessment exams for 6,7,8,9,11th standards. These exams are very competitive to all the students. So our website provides online tests for all the 6,7,8,9,11th standard’s subjects. These tests are also very effective and useful for those who preparing for any competitive exams like Olympiad etc. It can boost their preparation level and confidence level by attempting these chapter wise online tests.
These online tests are based on latest CBSE syllabus. While attempting these our students can identify the weak lessons and continuously practice those lessons for attaining high marks. It also helps to revise the NCERT textbooks thoroughly.
CBSE Class 11 Chemistry – MCQ and Online Tests – Unit 14 – Environmental Chemistry
Question 1.
A disease caused by eating fish contaminated by industrial waste, containing mercury compounds, is called as
(a) Minamata disease
(b) Brights disease
(c) Hashimotos disease
(d) Osteosclerosis
Answer
Answer: (a) Minamata disease
Explanation:
Disease caused by eating fish found in water contaminated with industrial waste having mercury is minamata disease.
Question 2.
Which of the following is responsible for depletion of ozone layer in the upper strata of the atmosphere?
(a) Polyhalogens
(b) Ferrocene
(c) Fullerencs
(d) Freons.
Answer
Answer: (d) Freons.
Explanation:
Fluorocarbons such as freon-1 (CFCl3) and freon-12 (CF2Cl2) emitted as propellants in aerosol spray cans, refrigerators, fire fighting reagents etc. are stable compounds and chemically inert. They do not react with any substance with which they come in contact and thus float through the atmosphere unchanged and eventually enter the stratosphere. There they absorb UV radiations and break down liberating free atomic chlorine which causes decomposition of ozone. This results in the depletion of the ozone layer.
Question 3.
The most harmful air pollutant produced by automobiles is
(a) HNO3
(b) NO
(c) SO2
(d) CO.
Answer
Answer: (d) CO.
Explanation:
Motor vehicle emissions contribute to air pollution and are a major ingredient in the creation of smog in some large cities. Transportation contributes to more than half of the carbon monoxide, sulphur dioxide and nitrogen oxides, and almost a quarter of the hydrocarbons emitted into our air. Carbon monoxide (CO) is a colourless, odourless, toxic non-irritating gas. It is a product by incomplete combustion of fuel such as natural gas, coal or wood. Vehicular exhaust is a major source of carbon monoxide.
Question 4.
Which of the following is responsible for depletion of ozone layer in the upper strata of the atmosphere?
(a) Polyhalogens
(b) Ferrocene
(c) Fullerencs
(d) Freons.
Answer
Answer: (d) Freons.
Explanation:
Fluorocarbons such as freon-1 (CFCl3) and freon-12 (CF2Cl2) emitted as propellants in aerosol spray cans, refrigerators, fire fighting reagents etc. are stable compounds and chemically inert. They do not react with any substance with which they come in contact and thus float through the atmosphere unchanged and eventually enter the stratosphere. There they absorb UV radiations and break down liberating free atomic chlorine which causes decomposition of ozone. This results in the depletion of the ozone layer.
Question 5.
Photochemical smog is related to pollution if
(a) Air
(b) Water
(c) Soil
(d) None of these
Answer
Answer: (c) Soil
Explanation:
Photochemical smog is produced when pollutants from the combustion of fossil fuels react with sunlight. The energy in the sunlight converts the pollutants into other toxic chemicals. For photochemical smog to form, there must be other pollutants in the air, specifically nitrous oxides and other volatile organic compounds (VOCs).
Question 6.
Which of the following acts as a sink for CO?
(a) Plants
(b) Haemoglobin
(c) Microorganisms present in the soil
(d) Oceans
Answer
Answer: (c) Microorganisms present in the soil
Explanation:
CO is converted into CO2 by microorganism present in soil.
Question 7.
Domestic waste mostly constitutes
(a) Non-biodegradable pollution
(b) Biodegradable pollution
(c) Effluents
(d) Air pollution
Answer
Answer: (b) Biodegradable pollution
Explanation:
Domestic waste mostly constitutes biodegradable pollution.
Question 8.
Which is most harmful for life on globe?
(a) Deforestation
(b) Soil Erosion
(c) Increasing Desert
(d) Nuclear Fallout.
Answer
Answer: (d) Nuclear Fallout.
Explanation:
Nuclear fallout, or simply fallout, is the residual radioactive material propelled into the upper atmosphere following a nuclear blast or a nuclear reaction conducted in an unshielded facility, so called because it “falls out” of the sky after the explosion and the shock wave have passed. While deforestation, soil erosion and increasing deserts can be controlled, nuclear fallout causes genetic mutation in humans and destruction that cannot be controlled or cured.
Question 9.
One of the following is the chief source of water and soil pollution
(a) Agro industry
(b) Mining
(c) Thermal power stations
(d) All of these
Answer
Answer: (c) Thermal power stations
Explanation:
Thermal power plant, agro industry and mining all are responsible for soil and water pollution. (Due to extraction of chemicals which cause pollution)
Question 10.
What is the indicator of pollution in water?
(a) Amount of oxygen
(b) Amount of hydrogen
(c) Amount of BOD
(d) Amount of nitrogen
Answer
Answer: (c) Amount of BOD
Explanation:
The amount of oxygen required to break down a certain amount of organic matter is called the biological oxygen demand (BOD). The amount of BOD in water is an indicator of the level of pollution.
Question 11.
The false statement among the followings:
(a) The average residence time of NO is one month.
(b) Limestone acts as a sink for SOx.
(c) SOx can be removed from flue gases by passing through a solution of citrate ions.
(d) Ammonia acts as a sink for NOx.
Answer
Answer: (d) Ammonia acts as a sink for NOx.
Explanation:
The average residence time of NO is 4 days.
Question 12.
The agricultural field that produces maximum methane gas into atmosphere is
(a) Wheat field
(b) Paddy field
(c) Cotton field
(d) Groundnut field
Answer
Answer: (c) Cotton field
Explanation:
Rice is grown in flooded fields, a situation that depletes the soil of oxygen. Soils that are anaerobic (lacking oxygen) allow the bacteria that produce methane from decomposing organic matter to thrive. Some of this methane then bubbles to the surface, but most of it is diffused back into the atmosphere through the rice plants themselves. Hence, rice Paddy field that produces maximum methane gas into the atmosphere.
Question 13.
Fluorosis, the bone disease, is caused by the presence of
(a) Pesticides in water
(b) Fluorides in water
(c) Carbon monoxide in air
(d) Sulphur dioxide in air.
Answer
Answer: (b) Fluorides in water
Explanation:
Skeletal fluorosis is a bone disease caused by excessive accumulation of fluoride in the bones. In advanced cases, skeletal fluorosis causes painful damage to bones and joints.
Question 14.
Why certain parts of water bodies contain more number of algae?
(a) Due to favorable environment
(b) Due to run-off excess fertilizers
(c) Due to lack of fertilizers
(d) Due to water pollution
Answer
Answer: (b) Due to run-off excess fertilizers
Explanation:
Inorganic plant nutrients found in fertilizers. Run-off carries excess fertilizers into nearby water bodies, causing high levels of plant nutrients which promote the excessive growth of algae and other aquatic plants.
Question 15.
The substance which is a primary pollutant?
(a) H2SO4
(b) CO
(c) PAN
(d) Aldehydes
Answer
Answer: (b) CO
Explanation:
Important Air pollutants
Oxides of carbon (CO,CO2)
Oxides of sulphur (SO2 & SO3)
Oxides of nitrogen
Chlorofluoro carbons (CFC)
Hydrocarbons Like CH4
?Photochemical and Industrial smog.
Dust & other particulate matter from industries.
Question 16.
Photochemical smog is related to pollution if
(a) Air
(b) Water
(c) Soil
(d) None of these
Answer
Answer: (c) Soil
Explanation:
Photochemical smog is produced when pollutants from the combustion of fossil fuels react with sunlight. The energy in the sunlight converts the pollutants into other toxic chemicals. For photochemical smog to form, there must be other pollutants in the air, specifically nitrous oxides and other volatile organic compounds (VOCs).
Question 17.
Identify the wrong statement in the following:
(a) Acid rain is mostly because of oxides of nitrogen and sulphur
(b) Chlorofluorocarbons are responsible for ozone layer depltion
(c) Greenhouse effect is responsible for global warming
(d) Ozone layer does not permit infrared radiation from the sun to reach the earth.
Answer
Answer: (d) Ozone layer does not permit infrared radiation from the sun to reach the earth.
Explanation:
Allotropes of Oxygen-
O2 (Dioxygen) and O3 (Ozone)
Infrared radiation is most important for heating up the atmosphere and the surface of the earth. These rays have high wavelength and low frequency and are not very harmful. Ozone does not hinder infrared radiation.
Question 18.
Synthesis of ethanal commercially from which of the following reagent is the part of green chemistry?
(a) CH3CH2OH
(b) CH2 = CH2
(c) HC = CH
(d) All of these
Answer
Answer: (b) CH2 = CH2
Question 19.
Which of the following is produced by a reaction of ultraviolet light?
(a) CO2
(b) SO2
(c) O3
(d) NO3
Answer
Answer: (c) O3
Explanation:
Ultraviolet radiations cause photochemical splitting of oxygen molecules in the stratosphere. The nascent oxygen combines with molecular oxygen to form ozone. In troposphere nascent oxygen comes from nitrogen dioxide.
Question 20.
Which of the following acts as a sink for CO?
(a) Plants
(b) Haemoglobin
(c) Microorganisms present in the soil
(d) Oceans
Answer
Answer: (c) Microorganisms present in the soil
Explanation:
CO is converted into CO2 by microorganism present in soil.
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