Lakshya Education MCQs

Question: Acid rain is caused by excess
A.Production of coal gas
B.Release of CO2 due to increasing combustion and respiration
C.Release of SO2 and NO from burning fossil fuels
D.Production of gaseous hydrocarbons
Answer: Option C
: C

Acid rain is caused by a chemical reaction that begins when compounds likesulphur dioxideandnitrogen oxidesare released into theair. These substances can rise very high into the atmosphere, where they mix and react with water,oxygen and other chemicals to form more acidic pollutants to precipitate down as acid rain.

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Question 1. Which of the following substances is non-biodegradable?
  1.    Paper
  2.    Radioactive substances
  3.    Biofertilisers
  4.    Glass
Answer: Option B
: B

Solid wastes that we generate in the environment can be categorised into three groups:
1. Biodegradable wastes are those wastes that are capable of being decomposed in a reasonable amount of time by bacteria or other living organisms and thus, do not cause pollution. Examples include human and animal waste, biofertilisers, kitchen waste etc.
2. Recyclable wastes are those that can be converted to reusable material. Glass, cardboard boxes, paper products, etc. are examples.
3. Non-biodegradable wastes those
that can not be broken down into their base compounds by microorganisms, air, moisture or soil in a reasonable amount of time. Radioactive elements, plastic, metal scraps etc. are non-biodegradable.
Question 2. Match the following:

Column 1Column 2(p)Scrubber(i) 1000 volts electrodes(q)Catalytic converter(ii)flue gas column(r)Electrostatic precipitator(iii)redox reactions

  1.    p - (iii), q - (ii), r - (i)
  2.    p - (ii), q - (iii), r - (i)
  3.    p - (i), q - (ii), r - (iii)
  4.    p - (ii), q - (i), r - (iii)
Answer: Option B
: B

A catalytic converter is an emission control device that converts toxic gases and pollutants in exhaust gas to less toxic pollutants by catalysing a redox reaction. They have metals like platinum, palladium and rhodium as catalysts and are fitted into automobiles to reduce emission of poisonous gases.
An electrostatic precipitator can remove close to 99% of particulate matter. It has electrodes that are maintained at several thousand volts, which produce a corona that releases electrons. These electrons attach to dust particles from the exhaust, giving them a net negative charge. The charged dust particles settle down as they are attracted to the collecting plates.
Scrubbers work on a single target pollutant and have water or designed adsorbent fluids, which are sprayed down through a rising column of flue gas. This motion of particles facilitates reactions and the pollutant gas dissolves in the wash, which is then purified or discarded.
Question 3. Which one of the following is not correct with regard to DDT?
  1.    DDT is biodegradable and does not undergoes biomagnification
  2.    DDT is non-biodegradable and undergoes biomagnification
  3.    DDT cannot be metabolised by the body
  4.    DDT is long lived and accumulates in fatty tissues
Answer: Option A
: A

Biomagnification is theprocess bywhich toxicsubstanceswhich cannot be metabolised by the body, startbecoming more and more concentrated at successive trophic levels. DDT was once, used extensively as a pesticide and was sprayed on crops to kill insects. However, it has beennoticed that through run off from fields, DDT enters streams and lakes, and enters the food chain of aquatic plants and animals. Because DDT is non-biodegradable, it keeps accumulating attoxic levels in living bodies.
Question 4. The major source(s) of emissions of SOx is/are
  1.    Smelting of ores
  2.    Combustion of petroleum
  3.    Petroleum refining
  4.    All of these
Answer: Option D
: D

Although there are natural sources of sulphur dioxide (accounting for 35-65% of the total sulphur dioxide emissions) such as volcanoes, most anthropogenic sulphur dioxide is produced by burning fuels containing sulphur or by roasting metal sulphide ores. Thermal power plants burning high-sulphur coal or heating oil are generally the main sources of sulphur dioxide emissions worldwide, followed by industrial boilers and nonferrous metal smelters. Emissions from domestic coal burning and from vehicles can also contribute to high concentrations of sulphur dioxide.
Question 5. In an area where DDT had been used extensively, the population of birds reduced significantly because
  1.    Birds stopped laying eggs
  2.    Earthworms in the area got eradicated
  3.    Cobras were feeding exclusively on birds
  4.    Many of the birds' eggs laid, did not hatch
Answer: Option D
: D

Biomagnification refers to an increase in concentration of atoxicant at successively higher trophic levels. This happens because a toxic substance accumulated by an organism cannot be metabolised or excretedand is thus, passed on in the food chain. DDT biomagnification occurs in aquatic food chains. If the concentration of DDT in water for instance, is 0.003 ppb (ppb = parts per billion) in water, that ultimately reaches25 ppm (ppm = parts per million) in fish-eating birds, through biomagnification. High concentration of DDT disturbs calcium metabolism in birds which causes thinning of egg shells and their premature breaking.
Question 6. Which of the following is/are true?

I. Benzene hexachloride is a non-biodegradable pollutant.

II. Anthropogenic air pollutants are natural in origin.

III. Carbon monoxide is a primary air pollutant.

IV. Sulphur dioxide causes brown air effect during traffic congestion in cities.
  1.    I and III
  2.    I and II  
  3.    II and III
  4.    II and IV
Answer: Option A
: A

Non-degradable pollutants either do not degrade,ormay degrade extremely slowly in the natural environment.e.g., DDT, BHC. Anthropogenic pollutants are man-made pollutants such as sewage, pesticides, fertilisers, etc. Primary air pollutants are those which pollute the air directly as soon as they get released from the source. Carbon monoxide is an example. In traffic congested cities, the brown air effect is caused due to oxides of nitrogen.

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