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CBSE Questions for Class 11 Medical Chemistry Environmental Chemistry Quiz 8 - MCQExams.com
CBSE
Class 11 Medical Chemistry
Environmental Chemistry
Quiz 8
Multiple Choice Questions
Depletion of which gas in the atmosphere can lead to an increased incidence of skin cancers.
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Methane
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Nitrous oxide
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Ozone
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Ammonia
In which layer of the atmosphere, ozone layer is present?
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Troposphere
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Stratosphere
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Mesosphere
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Thermosphere
Explanation
stratosphere
The ozone layer is mainly found in the lower portion of the stratosphere, from approximately 15 to 35 kilometers (9.3 to 21.7 mi) above Earth, although its thickness varies seasonally and geographically.
Most harmful pesticide is
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$$2, 4$$-D
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$$2, 4, 5$$-T
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DDT
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PAN
Explanation
A. 2,4-D or 2,4-dichlorophenoxyacetic acid is a herbicide used to kill weeds.
B. 2,4,5-T or 2,4,5-trichlorophenoxyacetic acid is a synthetic auxin, also used as a herbicide.
C.
Dichlorodiphenyltrichloroethane or DDT is most commonly used insecticide.
D. PAN or peroxyacetyl nitrate is a secondary pollutant which is present in photochemical smog.
Most harmful pesticide is DDT because it is nonbiodegradable and
on runoff from the fields , it reaches the water bodies and gets accumulated in the bodies of fishes. When fishes are eaten by birds, it gets accumulated in the body of birds and hence, in this way it enters the food chain. With each successive trophic level, concentration of DDT increases and this is known as biomagnification.
So, the correct answer is 'DDT'.
Which of the following statement is wrong?
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Ozone is produced in upper stratosphere by the action of UV rays on oxygen
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Ozone can oxidise sulphur dioxide present in the atmosphere to sulphur trioxide
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Ozone can oxidise sulphur dioxide layer present in stratosphere
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None of these
Explanation
given all of the option are correct by ozone side
Which gas is responsible for the depletion of ozone layer?
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Carbon dioxide
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Methane
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Chlorofluorocarbon
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Sulphur dioxide
Explanation
Chlorofluorocarbons (CFCs) and other halogenated ozone-depleting substances (ODS) are mainly responsible for man-made chemical ozone depletion.
$$CO_2$$ and $$CH_4$$ are greenhouse gases.
While $$SO_2$$ isn't a direct greenhouse gas like carbon dioxide or methane but it is considered a pollutant as it plays a role in acid rain.
Which of the following statement is false?
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Lower the concentration of D.O., the more polluted is the water sample
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The tolerable limit of lead in drinking water is $$50\ ppm$$
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Water is considered pure if it has BOD less than $$5\ ppm$$
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In COD determination, the pollutants resistant to microbial oxidation are not oxidized by an oxidizing agent like $$K_{2}Cr_{2}O_{7}$$
Explanation
In COD, the degradation is affected by an oxidizing agent, $$K_2 Cr_2 O_7.$$ COD is a measure of amount of oxygen , required to degrade or breakdown the organic matter.
Montreal Protocol is related to which of the following?
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Global Warming
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Deforestation
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Ozone layer depletion
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Sustainable development
Explanation
Ozone layer depletion,
Montreal Protocol, formally Montreal Protocol on Substances That Deplete the Ozone Layer, international treaty, adopted in Montreal on Sept. 16, 1987, that aimed to regulate the production and use of chemicals that contribute to the depletion of Earth’s ozone layer. Initially signed by 46 countries, the treaty now has nearly 200 signatories.
In the early 1970s, American chemists F. Sherwood Rowland and Mario Molina theorized that chlorofluorocarbon (CFC) compounds combine with solar radiation and decompose in the stratosphere, releasing atoms of chlorine and chlorine monoxide that are individually able to destroy large numbers of ozone molecules. (Along with Dutch chemist Paul Crutzen, Rowland and Molina were awarded the 1995 Nobel Prize for Chemistry for this work.) Their research, first published in the journal Nature in 1974, initiated a federal investigation of the problem in the United States, and the National Academy of Sciences concurred with their findings in 1976. In 1978 CFC-based aerosols were banned in the United States, Norway, Sweden, and Canada.
Further validation of their work came in 1985 with the discovery of a “hole” in the ozone shield over Antarctica by the British Antarctic Survey and the publication of its findings in Nature. Shortly before these findings were to appear, representatives from 28 countries met to discuss the issue at the Vienna Convention for the Protection of the Ozone Layer. The meeting called for international cooperation in research involving ozone-depleting chemicals (ODCs) and empowered the United Nations Environment Programme (UNEP) to lay the groundwork for the Montreal Protocol.
The initial agreement was designed to reduce the production and consumption of several types of CFCs and halons to 80 percent of 1986 levels by 1994 and 50 percent of 1986 levels by 1999. The protocol went into effect on Jan. 1, 1989. Since then the agreement has been amended to further reduce and completely phase out CFCs and halons, as well as the manufacture and use of carbon tetrachloride, trichloroethane, hydrofluorocarbons (HFCs), hydrochlorofluorocarbons (HCFCs), hydrobromofluorocarbons (HBFCs), methyl bromide, and other ODCs. Several subsequent meetings of the signing countries were convened to track overall progress toward this goal and to authorize new changes to the process of phasing out ODCs.
In which part of the atmosphere, ozone layer is present ?
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Stratosphere
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Troposphere
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Mesosphere
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Thermosphere
Consider the following statements.
a. Polyhydroxybutyrates are produced by bacterial fermentation.
b. Polyhydroxybutyrates can be used as biodegradable plastics.
c. Transgenic trees are used in producing polyhydroxybutyrates.
Which of the statements given is/are correct?
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$$1$$ only
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$$1$$ and $$2$$ only
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$$2$$ and $$3$$ only
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$$1, 2$$ and $$3$$
"The final Agent Orange raid in Vietnam took place in 1970; _______ areas have begun to bloom inBut 19 years after the war's end, it seem plain that Agent Orange is killing and maiming human beings, something it never intended to do. The apparent toxic fallout from those clouds ___ is a crop of human miseries including cancers, miscarriages and birth defects - that may persist for decades."
The offensive substance referred to in this quotation is
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A complex minute of DDT and other insecticides used as aerial sprays for protection against malaria and other tropical diseases
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A complex mixture of herbicides and weedicides used to increase agricultural output in the South Vietnam under the U.S. aid programme
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DOT used as an insecticide
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Dioxin used as defoliants
Explanation
Agent Orange was a herbicide mixture used by the U.S. military during the Vietnam War which contained a dangerous chemical contaminant called dioxin, however, continues to have the harmful impact today.
So, the correct option is 'Dioxin used as defoliants'.
The herbicide DCMU kills the weeds because it inhibits __________.
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respiration
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$$CO_{2}$$ fixation
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cell division
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$$NO_3^{2-}$$ uptake
Explanation
DCMU (Dichlorophenyl dimethyl urea) is a herbicide which kills the weeds by inhibiting $$CO_{2}$$ fixation as it is a strong inhibitor of photosystem II ($$P_{680}$$).DCMU acts by blocking electron flow at the guanine acceptors of PS II, by competing for the binding site of plastoquinone.
So the correct option is B.
'Thermal pollution' means dumping heat in an ecological system, like a lake or a pond. Thermal power plants have to throw some heat into a 'sink' because of they:
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get overheated
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have special anti-pollution laws
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follow the local sanitation laws
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follow the second natural law of thermodynamics
Explanation
Thermal pollution is the degradation of the quality of water due to a sudden change of its temperature. A primary source of thermal pollution is the discharge of heated water from the power plants. The unused heat, generally around $$60$$% of the input energy which is unable to be used in the process, is then returned to a sink, such as water.
One way of preventing pollution of the air is by passing exhaust gases through a filter. Glass fibre or silicone-treated bags of textile material are used for filtering.
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Hot gases
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High pressure gases
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Cold gases
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Reactive gases
Explanation
Silicone coated fiberglass bags are resistant to high temperatures and are able to separate at a temperature range of approximately $$-50^oC$$ to $$+250^oC$$. Thus it has excellent weather proof and water repellent properties. It is also resistant to chemicals. It is used to filtering hot gases as it can withstand high temperatures.
Read the following statements and select the correct option.
Statement 1: Ozone layer present in the stratosphere protects the living organisms from harmful UV rays coming from the sun by absorbing nearly all of them.
Statement 2: Ozone formed in the troposphere by photochemical reactions as a result of human activities which is harmful to all living organisms.
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Both statements 1 and 2 are correct.
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Statement 1 is correct but statement 2 is incorrect.
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Statement 1 is incorrect but statement 2 is correct.
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Both statements 1 and 2 are incorrect.
Explanation
'Good ozone' is found in the upper part of the atmosphere called the stratosphere and it act as a shield by absorbing ultraviolet radiations from the sun. UV rays are, highly injurious to living organisms. 'Bad ozone' is formed in the lower part of atmosphere called troposphere and it harms plants and animals.
The major ozone depleting substance out of the following is _____________.
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$$ { CFC }{ s } $$
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$$ { O }_{ 2 } $$
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Nitrogen
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All of these
Explanation
Ozone-depleting substances (ODS) are substances that react with ozone present in the stratosphere and destroy the same. The major Ozone-depleting substances are chlorofluorocarbons (14% of total depletion), nitrogen oxides (3.5% depletion), sulphur dioxide, halon, carbon tetrachloride, methyl chloroform, chlorine, etc.
An effective air-pollution control equipment is an attachment that electrically attracts pollutant particles in hot, escaping gases. It is known as:
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an electric condenser
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a gas condenser
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an air purifier
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an electrostatic precipitator
Explanation
Electrostatic precipitator is a device that uses an electric charge to remove certain impurities such as solid particles liquid from air and ether gases. It is particularly used to remove particles and power generating stations.
Pollution of lakes and rivers affects aquatic life. Fish cannot live in water that has oxygen less than $$4$$ milligrams per liter. Other freshwater aquatic life (including anaerobic bacteria) also cannot survive without adequate oxygen. 'BOD' stands for:
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Biological oxygen demand
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Bacterial oxygen deficit
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Basic oxygen demand
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Building oxygen deposits
Explanation
BOD stands for Biological Oxygen Demand is the amount of dissolved oxygen needed by aerobic biological organisms to break down organic material present in a given water sample at a certain temperature over a specific time period.
We need fresh air for breathing. Some sources that cause pollution of air are mentioned here. Can you pick the false one?
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Coal fires
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Heavy rain
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Volcanoes
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Forest fires
Explanation
Coal fires, volcanoes and forest fires causes air pollution due to release of many pollutants such as $$CO_2$$, whereas High-speed wind and dust storm cause pollution.
Heavy rain doesn't cause air pollution.
Option B
Which of the following statements regarding ozone is incorrect ?
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'Good ozone' is formed in the lower atmosphere (troposphere) that absorbs harmful UV rays coming from Sun, 'bad ozone' is present in the upper part of atmosphere (stratosphere) that harms plants and animals.
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The thickness of the ozone in a column of air from the ground to the top of the atmosphere is measured in terms of Dobson units (DU).
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Recognising the deleterious effects of ozone depletion, an international treaty, known as the Montreal Protocol, was signed at Montreal (canada) in 1987 (became effective in 1989) to control the emission of ozone depleting substances.
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None of these
Explanation
The good zone is formed in the ozone layer of the stratosphere and absorbs harmful UV rays coming from the Sun.
Bad ozone is formed in the troposphere in the lower atmosphere and harms plants and animals.
So, the incorrect option is '
'Good ozone' is formed in the lower atmosphere (troposphere) that absorbs harmful UV rays coming from Sun, 'bad ozone' is present in the upper part of the atmosphere (stratosphere) that harms plants and animals
'.
Ozone depletion is occurring widely in ______________.
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Troposphere
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Stratosphere
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Ionosphere
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All of these
Explanation
Ozone depletion is occurring widely in the stratosphere, particularly marked over the Antarctic region.
So, The correct answer is (B)- Stratosphere.
Sulphur oxides which are responsible for major air pollution are caused by:
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burning of coal and refining of pertoleum
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burning of fuels in automobiles
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combustion of fuels containing C and H
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using indoor combustion devices like cooking gas.
Explanation
$$SO_2$$ is a major gaseous pollutant found in the lower atmosphere. They are the compounds of sulphur and oxygen molecules. So when the fuels such as coal and oil are burnt, it leads to emission of
$$SO_2$$ gas.
Which of the following is not an air pollutant?
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$$H_{2}$$
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$$SO_{2}$$
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$$O_{3}$$
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$$NO_{x}$$
Explanation
$$SO_2, O_3, NO_x$$ causes pollution. They are examples of smog or photochemical smog. But $$H_2$$ being a clean fuel does not pollute the air.
Clean water would have Biochemical oxygen demand (BOD) value of less than:
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17 ppm
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5 ppm
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200,000 ppm
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10 ppm
Explanation
A water supply with a BOD level of 3-5 ppm is considered moderately clean. In water with a BOD level of 6-9 ppm, the water is considered somewhat polluted because there is usually organic matter present and bacteria are decomposing this waste.
Hence, clean water would have a BOD value of less than 5.
Hence, the correct option is $$\text{B}$$
Increasing skin cancer and high mutation rate are the result of _______________.
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Ozone depletion
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Acid rain
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$$CO$$ pollution
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$$ { CO }_{ 2 } $$ pollution
Explanation
Ozone depletion occurs widely in the stratosphere due to an increased amount of $$ { CFC }{ s } $$ which causes various types of skin cancer and mutations.
So, The correct answer is (A)- Ozone depletion.
The region which is greatly affected by air pollution is:
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troposphere
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stratosphere
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mesosphere
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thermosphere
Explanation
Regions of the atmosphere are given in increasing height as follows-
troposphere <stratosphere<mesosphere<thermosphere
Troposphere is the lowest layer of the atmosphere. Here, the formation of clouds takes place. The pollution in this layer occurs due to the presence of gaseous or solid particles in air. So this layer gets greatly affected by air pollution. Example: oxides of sulphur, carbon, dust, fumes etc,
Read the following statements carefully and select the incorrect ones.
(i) Development of the fertile top-soil takes centuries, but it can be easily removed due to human activities such as over-cultivation, unrestricted grazing, etc.
(ii) Waterlogging results in soil salinity.
(iii) UV rays are responsible for the degradation of the ozone shield in the atmosphere.
(iv) Ozone present in the stratosphere acts as a shield absorbing UV radiation coming from the Sun.
(v) Global warming can be controlled by increasing the use of fossil fuels.
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(i), (iii) and (v)
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(iii), (iv) and (v)
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(iv) and (v)
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(i), (ii) and (iii)
Explanation
Ozone present in the stratosphere act as a shield absorbing UV radiation coming from the sun.
Global warming can be controlled by cutting down the use of fossil fuels.
Which of the following pollutants is not harmful for lungs?
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$$CO$$
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$$CO_{2}$$
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$$SO_{2}$$
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$$NO_{2}$$
Explanation
The main components of gaseous pollutants are carbon monoxide, sulpur dioxide, nitrogen oxide. All of these pollutants damage lungs as when we breathe this dirty air, these pollutants enter directly deep into our lungs causing respiratory diseases and lung cancer.
The zone which extends above troposphere up to 50 km above sea level and contains dinitrogen, dioxygen, ozone and little water vapour is called:
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exosphere
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mesosphere
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ionosphere
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stratosphere
Explanation
Stratosphere ranges from 20-50 km. It is the layer above troposphere. Stratosphere contains ozone as it's main species.
Ultraviolet radiation is absorbed by:
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exosphere
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ionosphere
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ozonosphere
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stratosphere
Explanation
Answer:- (D) stratosphere
Due to the presence of ozone gas in the stratosphere, it strongly absorbs incoming UV radiation.
Green chemistry involves ?
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production of chemicals of our daily use from green house gases
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such chemical processes in which green plants are used
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those reaction which are of biological origin
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use of non-toxic reagents and solvents to produce environment friendly products.
Explanation
Green chemistry is a design of products and process that reduces or eliminates the use of harmful hazardous products. It uses the concept of invention and design and invokes to produce products that are environment-friendly.
Which of the following statements is not true?
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Ammonia acts as sink for $$NO_{x}$$.
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Limestone acts as sink for $$SO_{x}$$
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The average residence time of NO is one month.
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$$SO_{x}$$ can be removed from flue gases by passing through a solution of citrate ions.
Explanation
Residence time means the lifetime amount of chemicals in the atmosphere divided by the rate at which the chemicals are eliminated from the atmosphere. The average residence time of NO is 0.5 to 2 days.
Biological Oxygen Demand (BOD) can be defined as:
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the amount of oxygen required by bacteria to break down the organic matter of a sample of water
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the amount of chemicals required to break down the organic matter of a sample of water
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the amount of phosphate required to oxidise the organic matter of a sample of water
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the amount of organic matter present in the given sample of water
Explanation
BOD refers to the dissolved oxygen that the microorganisms like bacteria need to oxidize, means to break down inorganic and organic matter in water. It is a measure of water quality.
In Antarctica, ozone depletion is due to the formation of which of the following compounds?
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Acrolein
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$$SO_3$$ & $$SO_2$$
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Peroxyacyl nitrates
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Chlorine nitrate
Explanation
Ozone layer depletion is caused due to CFC's. So, chlorine nitrate, which is found in the stratosphere causes break down of the ozone layer. Chlorine is highly reactive and it interacts with ozone and hence destroys the ozone layer.
Freons are not recommended to be used in refrigerators because they:
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cause global warming
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cause acid rain
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cause depletion of ozone layer
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cause very less cooling
Explanation
Freon is basically a gas which is used for cooling. It is non-flammable substance, but if it leaks it smells like fresh-cut grass. As the CFC's causes depletion of the ozone layer, freons are not used as coolants anymore.
Ozone hole is maximum over:
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europe
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antarctica
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india
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africa
Explanation
When the solar radiations strikes the molecules of oxygen, it causes the two oxygen atoms to split apart. This is how ozone is created in stratosphere. Ozone also naturally occurs in stratosphere when sunlight reacts with nitrogen, hydrogen and chlorine. Greatest amount of ozone are formed at equtorial but when solar radiation is greatest. Daily variations are caused due to weather conditions.
Ultraviolet radiation is absorbed by :
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exosphere
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ionosphere
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mesosphere
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stratosphere
Explanation
As sunlight passes through the atmosphere, all UVC and approximately 90% of UVB radiation is absorbed by ozone, water vapour, oxygen and carbon dioxide. UVA radiation is less affected by the atmosphere.
B.O.D values of four samples of water A, B C and D are given below
A. 160 ppm
B. 35 ppm
C. 180 ppm
D. 25 ppm
The decreasing order of extent of pollution in water is ?
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C > A > D > B
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D > B > A > C
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C > A > B > D
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D > A > B > C
Explanation
BOD is the amount of oxygen dissolved in water, which is required by the micro organisms to oxidize inorganic and organic compounds. More amount of BOD means more polluted water. If the BOD is more than 17 ppm it is said to polluted. So, the decreasing order of content of polluted water is C>A>B>D.
The dissolution of ozone layer cause ozone hole in the blanket surrounding the atmosphere. What the ill effects of ozone hole?
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Greenhouse effect
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Global warming
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Acid rain
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UV rays reaching the earth.
Explanation
Ozone layer is a region in the stratosphere. It actually absorbs all the sun's ultraviolet radiations. If holes are formed in ozone layer then all the UV radiation will reach the earth surface directly and it then it will result in severe heath issues.
Ultraviolet radiation is absorbed by ?
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exosphere
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ionosphere
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ozonosphere
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stratosphere.
Explanation
The stratosphere is the second layer of the earth's atmosphere and extends up-to $$50$$ kilometres high. Most of the ultraviolet radiation, about $$99\%$$ radiation reaching the earth' s surface from the sun is absorbed by the stratosphere.
Which of the following pairs is not correctly matched?
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Allotropic form of sulphur which is more stable at room temperature - Rhombic
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The hydride of group 16 which is liquid at room temperature - Water
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The gas formed in the upper layers of atmosphere by action of U V radiations - Nitrogen
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The catalyst used in the manufacture of $$H_{2}SO_{4}$$ by contact process - Vanadium pentoxide
Explanation
Rhombic sulphur is most stable form of sulphur at room temperature. $$H_2O$$ is group $$VI$$ hydride which is a liquid. Ozone is the gas formed in the upper layer of atmosphere by action of UV rays $$V_2O_5$$ is used to catalyze in contact process.
Biochemical Oxygen Demand (BOD) is a measure of organic material present in water. BOD value less than 5 ppm indicates a water to be ________.
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rich in dissolved oxygen
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poor in dissolved oxygen
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highly polluted
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not suitable for aquatic life
Explanation
Clean water has BOD which is less than 5 ppm. If it is equal to or more than 12 ppm, then the water is considered as polluted. So this indicates water be rich in dissolved oxygen, that helps the microorganisms to oxidize inorganic and organic materials.
Match the column I with column II and mark the appropriate choice.
Column I
Column II
(A)
Troposphere
(i)
Prevents UV rays coming to earth
(B)
Stratosphere
(ii)
Ionization of gases
(C)
Mesosphere
(iii)
Maintenance of heat balance
(D)
Thermosphere
(iv)
Non-propagation of sound waves
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(A) $$\rightarrow$$ (ii), (B) $$\rightarrow$$ (iv), (C) $$\rightarrow$$ (iii), (D) $$\rightarrow$$ (i)
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(A) $$\rightarrow$$ (iv), (B) $$\rightarrow$$ (ii), (C) $$\rightarrow$$ (i), (D) $$\rightarrow$$ (iii)
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(A) $$\rightarrow$$ (iii), (B) $$\rightarrow$$ (i), (C) $$\rightarrow$$ (iv), (D) $$\rightarrow$$ (ii)
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(A) $$\rightarrow$$ (i), (B) $$\rightarrow$$ (iii), (C) $$\rightarrow$$ (ii), (D) $$\rightarrow$$ (iv)
Pollution is:
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removal of top soil
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release of toxic/undesirable materials in environment
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conservation of energy
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all of the above
Explanation
Pollution is defined as the introduction of contaminants into the natural environment that cause adverse change. Pollution can take the form of chemical substances or energy, such as noise, heat, or light. Pollutants, the components of pollution, can be either foreign substances/energies or naturally occurring contaminants.
From the given options, we can say that pollution is the release of toxic/undesirable materials in the environment.
Multiple Choice Questions
In an area where DDT had been used extensively, the bird population declined significantly due to
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Birds stopped laying eggs
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earthworms disappeared from the area
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many of the birds eggs did not hatch
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snakes started feeding exclusively on birds.
Explanation
For an area where DDT had been used extensively, there's a likelihood of its biomagnification.
Biomagnification refers to an increase in concentration of toxic substances due to its accumulation at successive trophic levels. Biomagnificatio
n of DDT disturbs calcium metabolism in birds leading to thinning of eggshells and its premature breaking or underdevelopment ceasing its hatching. This leads to a significant decrease in their population.
So, the correct answer is option C, many of the birds eggs did not hatch.
Which of the following is a sink for CO?
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Haemoglobin
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Microorganism presence in the soil
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Ocean
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Plant
Explanation
Microorganism presence in the soil is the sink for CO.
Ozone layer depletion may lead to which of the following harmful effects in organisms?
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Skin cancer
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Cataract
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Damage to the immune system
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All of the above
Explanation
Ozone gas is found in the stratosphere of the atmosphere. The ozone layer protects the earth from the harmful ultraviolet rays emitted from the sun. Ozone layer depletion has many adverse serious environmental effects. It may result in global warming. The ultraviolet radiations exposure leads to skin cancer like malignant melanoma. It also increases the rate of ageing in an individual. It also has harmful effect on the eyes. It may cause cataract. Immune system is also affected by this harmful ultraviolet radiations. Apart from humans, ozone layer depletion affects marine, aquatic and other forms of life as well.
Thus, the correct answer is 'All of the above.'
Negative soil pollution is:
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reduction in soil productivity due to erosion and over use
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reduction in soil productivity due to addition of pesticides and industrial wastes
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converting fertile land into barren land by dumping ash, sludge and garbase
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none of the above
Explanation
Negative soil pollution occurs due to the overuse of soil & its erosion hence there will be a decrease in soil productivity.
The other causes of negative soil pollution such as developmental activities, overgrazing and soil erosion.
Modes of controlling pollution in large cities include :
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less use of insecticides
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proper disposal of organic wastes, sewage and industrial effluents
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shifting of factories out of the residential area
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all of the above
Explanation
A person who is exposed to small amounts of insecticides over a long period of time can experience the effects of chronic poisoning and also pesticide spray can drift and pollute the air. Thus less use of insecticides should be done.
Also, proper disposal of organic waste, sewage, and industrial waste also reduce pollution.
Shifting large factories out of the residential area prevents less human contact with the pollution.
Hence, all options are the correct modes of controlling pollution in large cities.
The maximum hole of ozone is found over ______
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Arctic zone
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Antarctic zone
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Tropical zone
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Subtropical zone
Explanation
Ozone-depleting substances are present throughout the stratospheric ozone layer because they are transported great distances
by atmospheric air motions. The severe depletion of the Antarctic ozone layer known as the “ozone hole” occurs
because of the special atmospheric and chemical conditions that exist there and nowhere else on the globe. The very low
winter temperatures in the Antarctic stratosphere cause polar stratospheric clouds (PSCs) to form. Special reactions that
occur on PSCs, combined with the relative isolation of polar stratospheric air, allow chlorine and bromine reactions to produce
the ozone hole in Antarctic springtime.
So, the correct answer is 'Antarctic zone'.
Which one of the following is not an application of green chemistry?
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Replacement of CFCs by $${CO}_{2}$$ as lowing agent in the manufacture of polystyrene foam sheets
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Reacting methylamine and phsogene to produce metyl isocyanate
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Replacement of organotions by sea-nine as anti fouling compound in sea marines
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Catalytic dehydrogenation of the diethanol amine withou using cyanide and formaldehyde
Explanation
$$ \begin{array}{l} \text { B) Reacting methylamine and phosgene to produce } \\ \text { methye iseocynate } \text { . is not an } \\ \text { application of green chemistry as methye } \\ \text { isougnate is extremely tonic and } \\ \text { was cheif carse of Bhopal Gas Tragedy. } \end{array} $$
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Practice Class 11 Medical Chemistry Quiz Questions and Answers
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