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Assertion (A): If BOD level of water in a reservoir is less than 5 ppm it is highly polluted. Reason (R): High biological oxygen demand means low activity of bacteria in water. - Chemistry

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प्रश्न

Assertion (A): If BOD level of water in a reservoir is less than 5 ppm it is highly polluted.

Reason (R): High biological oxygen demand means low activity of bacteria in water.

विकल्प

  • Both A and R are correct and R is the correct explanation of A.

  • Both A and R are correct but R is not the correct explanation of A.

  • Both A and R are not correct.

  • A is not correct but R is correct.

MCQ

उत्तर

Both A and R are not correct.

Explanation:

Since the amount of oxygen required by bacteria to breakdown the organic matter present in a certain volume of a sample of water, is called BOD i.e., Biochemical Oxygen Demand. If the BOD of the water is < 5 ppm then it is clean but if it increases then the water pollution increases.

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Environmental Pollution - Introduction
  क्या इस प्रश्न या उत्तर में कोई त्रुटि है?
अध्याय 14: Environmental Chemistry - Multiple Choice Questions (Type - I) [पृष्ठ १८३]

APPEARS IN

एनसीईआरटी एक्झांप्लर Chemistry [English] Class 11
अध्याय 14 Environmental Chemistry
Multiple Choice Questions (Type - I) | Q 45 | पृष्ठ १८३

संबंधित प्रश्न

Define environmental chemistry.


What is degradable pollutants?


Which one of the following rivers is highly polluted?


The disposal of urban waste has become a serious concern for the local authorities. Analyze the statement with suitable examples.


What are biodegradable and non-biodegradable pollutants?


Match the activity given in Column I with the type of pollution created by it given in Column II.

  Column I (Activity)   Column II (Effect)
(i) Releasing gases to the atmosphere
after burning waste material
containing sulphur.
(a) Water pollution
(ii) Using carbamates as pesticides (b) Photochemical smog,
damage to plant life,
corrosion to building
material, induce breathing
problems, water pollution
(iii) Using synthetic detergents for
washing clothes
(c) Damaging ozone laye
(iv) Releasing gases produced by
automobiles and factories in the
atmosphere.
(d) May cause nerve diseases
in human.
(v) Using chlorofluorocarbon compounds
for cleaning computer parts
(e) Classical smog, acid rain,
water pollution, induce
breathing problems,
damage to buildings,
corrosion of metals.

Which of these sources are responsible for water pollution?

  1. Households
  2. Industries
  3. Farms and fields
  4. Tourism

Hepatitis A is transmitted due to


Respiratory diseases are mainly caused by ______ pollution.


Read the given source and answer the questions that follow: 

The main sources of noise pollution are various factories, mechanized construction and demolition Works, automobiles and aircraft, etc. There may be added periodical but polluting noise from sirens, loudspeakers used in various festivals, programmes associated with community activities. The level of steady noise is measured by sound level expressed in terms of decibels (dB).

Of all these sources, the biggest nuisance is the noise produced by traffic, because its intensity and nature depend upon factors, such as the type of aircraft, vehicle, train and the condition of road, as well as, that of vehicle (in case of automobiles). In sea traffic, the noise pollution is confined to the harbour due to loading and unloading activities being carried. Industries cause noise pollution but with varying intensity depending upon the type of industry.

Noise pollution is location specific and its intensity declines with increase in distance from the source' of pollution, i.e. industrial areas, arteries of transportation, airport, etc. Noise Pollution is hazardous in many metropolitan and big cities in India.

  1. Explain the meaning of noise pollution.
  2. Why is noise pollution hazardous in metropolitan cities in India? 
  3. "Noise pollution is location specific." Explain with argument. 

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