CBSE Questions for Class 11 Medical Chemistry Environmental Chemistry Quiz 8 - MCQExams.com

Multiple Choice Questions
Depletion of which gas in the atmosphere can lead to an increased incidence of skin cancers.
  • Methane
  • Nitrous oxide
  • Ozone
  • Ammonia
In which layer of the atmosphere, ozone layer is present?
  • Troposphere
  • Stratosphere
  • Mesosphere
  • Thermosphere
Most harmful pesticide is
  • $$2, 4$$-D
  • $$2, 4, 5$$-T
  • DDT
  • PAN
Which of the following statement is wrong?
  • Ozone is produced in upper stratosphere by the action of UV rays on oxygen
  • Ozone can oxidise sulphur dioxide present in the atmosphere to sulphur trioxide
  • Ozone can oxidise sulphur dioxide layer present in stratosphere
  • None of these
Which gas is responsible for the depletion of ozone layer?
  • Carbon dioxide
  • Methane
  • Chlorofluorocarbon
  • Sulphur dioxide
Which of the following statement is false?
  • Lower the concentration of D.O., the more polluted is the water sample
  • The tolerable limit of lead in drinking water is $$50\ ppm$$
  • Water is considered pure if it has BOD less than $$5\ ppm$$
  • In COD determination, the pollutants resistant to microbial oxidation are not oxidized by an oxidizing agent like $$K_{2}Cr_{2}O_{7}$$
Montreal Protocol is related to which of the following?
  • Global Warming
  • Deforestation
  • Ozone layer depletion
  • Sustainable development
In which part of the atmosphere, ozone layer is present ?
  • Stratosphere
  • Troposphere
  • Mesosphere
  • 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?
  • $$1$$ only
  • $$1$$ and $$2$$ only
  • $$2$$ and $$3$$ only
  • $$1, 2$$ 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
  • A complex minute of DDT and other insecticides used as aerial sprays for protection against malaria and other tropical diseases
  • A complex mixture of herbicides and weedicides used to increase agricultural output in the South Vietnam under the U.S. aid programme
  • DOT used as an insecticide
  • Dioxin used as defoliants
The herbicide DCMU kills the weeds because it inhibits __________.
  • respiration
  • $$CO_{2}$$ fixation
  • cell division
  • $$NO_3^{2-}$$ uptake
'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:
  • get overheated
  • have special anti-pollution laws
  • follow the local sanitation laws
  • follow the second natural law of thermodynamics
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.
  • Hot gases
  • High pressure gases
  • Cold gases
  • Reactive gases
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.
  • Both statements 1 and 2 are correct.
  • Statement 1 is correct but statement 2 is incorrect.
  • Statement 1 is incorrect but statement 2 is correct.
  • Both statements 1 and 2 are incorrect.
The major ozone depleting substance out of the following is _____________.
  • $$ { CFC }{ s } $$
  • $$ { O }_{ 2 } $$
  • Nitrogen
  • All of these
An effective air-pollution control equipment is an attachment that electrically attracts pollutant particles in hot, escaping gases. It is known as:
  • an electric condenser
  • a gas condenser
  • an air purifier
  • an electrostatic precipitator
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:
  • Biological oxygen demand
  • Bacterial oxygen deficit
  • Basic oxygen demand
  • Building oxygen deposits
We need fresh air for breathing. Some sources that cause pollution of air are mentioned here. Can you pick the false one?
  • Coal fires
  • Heavy rain
  • Volcanoes
  • Forest fires
Which of the following statements regarding ozone is incorrect ?
  • '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.
  • 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).
  • 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.
  • None of these
Ozone depletion is occurring widely in ______________.
  • Troposphere
  • Stratosphere
  • Ionosphere
  • All of these
Sulphur oxides which are responsible for major air pollution are caused by:
  • burning of coal and refining of pertoleum
  • burning of fuels in automobiles
  • combustion of fuels containing C and H
  • using indoor combustion devices like cooking gas.
Which of the following is not an air pollutant?
  • $$H_{2}$$
  • $$SO_{2}$$
  • $$O_{3}$$
  • $$NO_{x}$$
Clean water would have Biochemical oxygen demand (BOD) value of less than:
  • 17 ppm
  • 5 ppm
  • 200,000 ppm
  • 10 ppm
Increasing skin cancer and high mutation rate are the result of _______________.
  • Ozone depletion
  • Acid rain
  • $$CO$$ pollution
  • $$ { CO }_{ 2 } $$ pollution
The region which is greatly affected by air pollution is:
  • troposphere
  • stratosphere
  • mesosphere
  • thermosphere
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.
  • (i), (iii) and (v)
  • (iii), (iv) and (v)
  • (iv) and (v)
  • (i), (ii) and (iii)
Which of the following pollutants is not harmful for lungs?
  • $$CO$$
  • $$CO_{2}$$
  • $$SO_{2}$$
  • $$NO_{2}$$
The zone which extends above troposphere up to 50 km above sea level and contains dinitrogen, dioxygen, ozone and little water vapour is called:
  • exosphere
  • mesosphere
  • ionosphere
  • stratosphere
Ultraviolet radiation is absorbed by:
  • exosphere
  • ionosphere
  • ozonosphere
  • stratosphere
Green chemistry involves ?
  • production of chemicals of our daily use from green house gases
  • such chemical processes in which green plants are used
  • those reaction which are of biological origin
  • use of non-toxic reagents and solvents to produce environment friendly products.
Which of the following statements is not true?
  • Ammonia acts as sink for $$NO_{x}$$.
  • Limestone acts as sink for $$SO_{x}$$
  • The average residence time of NO is one month.
  • $$SO_{x}$$ can be removed from flue gases by passing through a solution of citrate ions.
Biological Oxygen Demand (BOD) can be defined as:
  • the amount of oxygen required by bacteria to break down the organic matter of a sample of water
  • the amount of chemicals required to break down the organic matter of a sample of water
  • the amount of phosphate required to oxidise the organic matter of a sample of water
  • the amount of organic matter present in the given sample of water
In Antarctica, ozone depletion is due to the formation of which of the following compounds?
  • Acrolein
  • $$SO_3$$  &   $$SO_2$$
  • Peroxyacyl nitrates
  • Chlorine nitrate
Freons are not recommended to be used in refrigerators because they:
  • cause global warming
  • cause acid rain
  • cause depletion of ozone layer
  • cause very less cooling
Ozone hole is maximum over:
  • europe
  • antarctica
  • india
  • africa
Ultraviolet radiation is absorbed by :
  • exosphere
  • ionosphere
  • mesosphere
  • stratosphere
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 ?
  • C > A > D > B
  • D > B > A > C
  • C > A > B > D
  • D > A > B > C
The dissolution of ozone layer cause ozone hole in the blanket surrounding the atmosphere. What the ill effects of ozone hole?
  • Greenhouse effect
  • Global warming
  • Acid rain
  • UV rays reaching the earth.
Ultraviolet radiation is absorbed by ?
  • exosphere
  • ionosphere
  • ozonosphere
  • stratosphere.
Which  of the following pairs is not correctly matched?
  • Allotropic form of sulphur which is more stable at room temperature - Rhombic
  • The hydride of group 16 which is liquid at room temperature - Water
  • The gas formed in the upper layers of atmosphere by action of U V radiations - Nitrogen
  • The catalyst used in the manufacture of $$H_{2}SO_{4}$$ by contact process - Vanadium pentoxide
Biochemical Oxygen Demand (BOD) is a measure of organic material present in water. BOD value less than 5 ppm indicates a water to be ________.
  • rich in dissolved oxygen
  • poor in dissolved oxygen
  • highly polluted
  • not suitable for aquatic life
Match the column I with column II and mark the appropriate choice.
Column IColumn 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
  • (A) $$\rightarrow$$ (ii), (B) $$\rightarrow$$ (iv), (C) $$\rightarrow$$ (iii), (D) $$\rightarrow$$ (i)
  • (A) $$\rightarrow$$ (iv), (B) $$\rightarrow$$ (ii), (C) $$\rightarrow$$ (i), (D) $$\rightarrow$$ (iii)
  • (A) $$\rightarrow$$ (iii), (B) $$\rightarrow$$ (i), (C) $$\rightarrow$$ (iv), (D) $$\rightarrow$$ (ii)
  • (A) $$\rightarrow$$ (i), (B) $$\rightarrow$$ (iii), (C) $$\rightarrow$$ (ii), (D) $$\rightarrow$$ (iv)
Pollution is:
  • removal of top soil
  • release of toxic/undesirable materials in environment
  • conservation of energy
  • all of the above
Multiple Choice Questions
In an area where DDT had been used extensively, the bird population declined significantly due to
  • Birds stopped laying eggs
  • earthworms disappeared from the area
  • many of the birds eggs did not hatch
  • snakes started feeding exclusively on birds.
Which of the following is a sink for CO?
  • Haemoglobin
  • Microorganism presence in the soil
  • Ocean
  • Plant
Ozone layer depletion may lead to which of the following harmful effects in organisms?
  • Skin cancer
  • Cataract
  • Damage to the immune system
  • All of the above
Negative soil pollution is:
  • reduction in soil productivity due to erosion and over use
  • reduction in soil productivity due to addition of pesticides and industrial wastes
  • converting fertile land into barren land by dumping ash, sludge and garbase
  • none of the above
Modes of controlling pollution in large cities include :
  • less use of insecticides
  • proper disposal of organic wastes, sewage and industrial effluents
  • shifting of factories out of the residential area
  • all of the above
The maximum hole of ozone is found over ______
  • Arctic zone
  • Antarctic zone
  • Tropical zone
  • Subtropical zone
Which one of the following is not an application of green chemistry?
  • Replacement of CFCs by $${CO}_{2}$$ as lowing agent in the manufacture of polystyrene foam sheets
  • Reacting methylamine and phsogene to produce metyl isocyanate
  • Replacement of organotions by sea-nine as anti fouling compound in sea marines
  • Catalytic dehydrogenation of the diethanol amine withou using cyanide and formaldehyde
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Practice Class 11 Medical Chemistry Quiz Questions and Answers