Tag: environmental pollution

Questions Related to environmental pollution

A secondary pollutant is

zoology environmental pollution primary air pollutants air pollution - types and sources not for breathing not for drinking

  1. CO

  2. $CO _2$

  3. PAN

  4. Aerosol

Show answer
Correct Option: C
Explanation:

The photochemical smog has the chief constituent of the peroxy-acetyl nitrate (PAN) that are secondary pollutants as they formed by the primary pollutants. These are formed when the hydrocarbon radicals react with the oxygen in the presence of the sunlight. It forms a brown-coloured haze. This also results in the formation of the ground-level ozone. 

So, the correct answer is 'PAN'

Which one of the following acts as secondary pollutants?

zoology environmental pollution primary air pollutants air pollution - types and sources not for breathing not for drinking

  1. Br

  2. $NO _2$

  3. $HNO _3$

  4. $Cl _2$

Show answer
Correct Option: B
Explanation:
Pollutants may be primary or secondary.
  • Primary pollutants are the pollutants that are directly released or emitted in the atmosphere. 
  • Secondary pollutants are the pollutants which are formed when primary pollutants react with themselves or with other components of atmosphere.
An example of secondary pollutant is NO2 which is formed when NO reacts with oxygen in air.
So, the correct answer is 'NO2'.

Examples of secondary air pollutants is/are

zoology environmental pollution primary air pollutants air pollution - types and sources not for breathing not for drinking

  1. Smog

  2. PAN

  3. $O _3$

  4. All of the above

Show answer
Correct Option: D
Explanation:

Secondary pollutant is an air pollutant that do not emit directly from the source but forms when primary pollutant reacts in the atmosphere. For example $O _3$ and PAM forms when hydrocarbon reacts with nitrogen oxides in the presence of sunlight, smog forms when industrial or vehicle fumes reacts with sunlight in atmosphere. Thus, the correct answer is 'All of the above'.

Given below are some differences between primary air pollutants and secondary air pollutants.


Which one of the following is an incorrect difference?

zoology environmental pollution primary air pollutants air pollution - types and sources not for breathing not for drinking

  1. (i) Primary air pollutants - These persist in the form in which they are added to the environment.

    (ii) Secondary air pollutants - these are formed by interaction among the primary pollutants.

  2. (i) Primary air pollutants - These are more toxic than the secondary pollutants.

    (ii) Secondary air pollutants - These are less toxic than the primary pollutants.

  3. (i) Primary air pollutants - Examples include DDT, $ { CO } _{ 2 } $

    (ii) Secondary air pollutants - Examples include Ozone, PAN

  4. None of these

Show answer
Correct Option: B

Read the following statements regarding the PAN (peroxyacyl nitrates) and select the correct ones.
(i) It is a secondary pollutant present in photochemical smog.
(ii) It is produced by photochemical reactions between hydrocarbons and nitrogen oxides in the presence of sunlight of UV radiations.
(iii) It is thermally unstable and decomposes into peroxyethanoyl radicals and nitrogen dioxide gas. 
(iv) It is a lachrymatory substance, causing irritation of eyes.

zoology environmental pollution primary air pollutants air pollution - types and sources not for breathing not for drinking

  1. (i) and (ii)`

  2. (iii) and (iv)

  3. (i), (ii), and (iii)

  4. (i), (ii), (iii) and (iv)

Show answer
Correct Option: D
Explanation:

Secondary pollutants are pollutants which form in the atmosphere. These pollutants are not emitted directly from a source (like vehicles or power plants). Instead, they form as a result of the pollutants emitted from these sources reacting with molecules in the atmosphere. Secondary pollutants are concerning as they can be formed from many different compounds. Photochemical smog is made up of various secondary pollutants like ozone, peroxyacyl nitrates (PANs), and nitric acid.

A hazy condition of the atmosphere caused by the reaction of hydrocarbons with molecules of nitrogen oxide in sunlight, which produces complex organic molecules of peroxyacetyl nitrates (PAN). In humid conditions these molecules produce smog. Such phenomena are common in large urban areas (e.g. the Los Angeles basin and Athens) where there are stable atmospheric conditions and a high level of hydrocarbon input from incomplete combustion in car engines. Natural photochemical reactions occur in the high atmosphere with the absorption of radiation by oxygen to produce ozone. 
Peroxyacetyl nitrate (PAN; CH3C(O)OONO2) is an important constituent of photochemical smog. It is also a ubiquitous chemical present throughout the global troposphere. PAN is thermally unstable, however, and decomposes at higher temperatures to reform peroxyacetyl radicals and NO2, that is, the reverse of reaction.
Peroxyacyl nitrates (also known as Acyl peroxy nitrates, APN or PANs) are powerful respiratory and eye irritants present in photochemical smog. They are lachrymators, causing eye irritation at concentrations of only a few parts per billion. At higher concentrations they cause extensive damage to vegetation.
So the correct option is '(i), (ii), (iii) and (iv)'.

The following table summarises the differences between biodegradable and non-biodegradable pollutants. Pick out the wrong differences and select the correct answer.

Biodegradablepollutants Non-biodegradablepollutants
(i) These are the pollutants that can be easily degraded by micro-organisms. These are the pollutants that can not be degraded into harmless materials.
(ii) These can be used to produce energy (through biogas), compost, manure, etc. These are difficult to manage as a natural method of degradation is absent.
(iii) These usually do not enter biogeochemical cycles. These become a part of rapid turnover in biogeochemical cycles.
(iv) Examples: DDT, BHC, plastics, polyethylene, glass, etc. Examples: Sewage, garbage, animal waste, etc.
zoology environmental pollution primary air pollutants air pollution - types and sources not for breathing not for drinking

  1. (i) and (iv)

  2. (ii) and (iv)

  3. (iii) and (iv)

  4. (ii), (iii) and (iv)

Show answer
Correct Option: C
Explanation:

Biodegradable pollutants become part of rapid turnover in biogeochemical cycles. The examples of biodegradable pollutants are sewage, garbage, animal waste and livestock. Most non-biodegradable pollutants do not enter biogeochemical cycle e. g., DDT, BHC, plastics, polyethylene, cans, glass, etc.

Primary pollutants in photochemical smog are nitric oxides and

zoology environmental pollution primary air pollutants air pollution - types and sources not for breathing not for drinking

  1. Hydrocarbons

  2. Fluorocarbons

  3. Hydrofluorocarbons

  4. Hydrocortone

Show answer
Correct Option: A

The chemical name of freon is 

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  1. Dichloroflouro methane

  2. Trichlorotriflouro ethane

  3. Dichlorofluorine

  4. Dichlorodifluoromethane

Show answer
Correct Option: D
Explanation:

Dichlorodifluoromethane (R-12) is a colorless gas usually sold under the brand name Freon-12. Thus, the chemical name of freon is chlorodifluoromethane. It is used as a refrigerant and aerosol spray propellant. 

One of the following acts as secondary pollutant.

zoology environmental pollution primary air pollutants air pollution - types and sources not for breathing not for drinking

  1. Br$ _2$

  2. O$ _3$

  3. Cl$ _2$

  4. CO

Show answer
Correct Option: B
Explanation:

Secondary pollutants are the pollutants formed by the chemical reaction between primary pollutants in the presence of sunlight e.g., sulphuric acid, nitrogen dioxide and ozone. 

In pollution, the term 'synergism' is used for

zoology environmental pollution primary air pollutants air pollution - types and sources not for breathing not for drinking

  1. Biomagnification of nondegradable pollutants

  2. Dangerous effect when two pollutants are present together

  3. Decreasing effect to a degradable pollutant

  4. Formation of more potent secondary pollutant from primary pollutants

Show answer
Correct Option: D
Explanation:

Synergism means the process of acting together. In pollution, the synergism is seen when the primary pollutants are less harmful but they combine to form a more potent secondary pollutant. For example, the presence of ozone in the troposphere is undesired and this ozone has come due to the combination of hydrocarbons and nitrogen oxides (both are primary pollutants).

Hence, the correct answer is 'Formation of more potent secondary pollutant from primary pollutants'