Pollution MCQ Quiz in मराठी - Objective Question with Answer for Pollution - मोफत PDF डाउनलोड करा

The correct answer is that Neither heavy metals nor organic compounds

Key Points

• Phenol and phenolic compounds are among the most prevalent refractory chemical pollutants in wastewater released from industries.
• A number of methods including chemical, physical, electrochemical, and anaerobic biological processes can treat phenolic wastes.
• They are released mainly by oil refineries, phenol–formaldehyde resin, and bulk drug manufacturing industries.
• A number of poorly biodegradable refractory pollutants like petroleum hydrocarbons, sulfides, aniline, naphthalenic acid, organochlorines, olefins, nitrobenzene, alkanes, and chloroalkanes, generated by the petrochemical industries are present in wastewater.
• The composition of petrochemical wastes is chemically very complex and their treatment by biological methods is slow and not very effective.
• Even after the primary biological treatment, the organic pollutants are retained in the secondary effluents.
• They require chemical oxidants for the formation of inorganic end products and thus exhibit a low ratio of biological oxygen demand (BOD) to chemical oxygen demand (COD).
• Suspended solids and highly organic materials are the major water pollutants released by the paper and pulp industry. Hence option 1st is Incorrect.
• Depending on the quality of paper produced and pulp processing, the characteristics of the effluent change.

Concept:

• The quantity of oxygen consumed by bacteria and other microorganisms while they decompose organic matter under aerobic conditions at a specified temperature is known as Biochemical Oxygen Demand (BOD).
• Water bodies contain small amounts of oxygen, in the form of dissolved oxygen.
• Although the amount of dissolved oxygen is small, up to about ten molecules of oxygen per million of water, it is a crucial component of natural water bodies; the presence of a sufficient concentration of dissolved oxygen is critical to maintaining aquatic life and the aesthetic quality of streams and lakes.

• The greater the BOD, the more rapidly oxygen is depleted in the stream.

• This means less oxygen is available to higher forms of aquatic life.

• The consequences of the high BOD are the same as those of low dissolved oxygen: aquatic organisms become stressed, suffocate, and die.

• BOD in drinking water should be zero, which means that there are no microorganisms in it.

Explanation:

Option 1) Remains unchanged when algal bloom occurs- INCORRECT

• When algal bloom occurs BOD changes as the oxygen demand changes.
• This option is incorrect

Option 2) Increases when sewages get mixed with river water- CORRECT

• BOD is the amount of oxygen needed to decompose organic matter.
• If sewages get mixed with river water then the water will be polluted as a result more will be the BOD as more will be organic matter present in it, and hence, more oxygen will be required to decompose it.

Option 3) Gives a measure of salmonella in the water- INCORRECT

• BOD does not measure salmonella in the water
• This option is incorrect

Hence, the correct answer is Option (2).

Concept:

• Pollutants are those substances that cause harmful effects on the environment.
• Pollutants can be natural (like minerals) or man-made(pollutants from vehicles, and manufactured materials).
• Pollutants cause harmful effects on the environment and they can be long-term or short-term damage depending on the type of pollutant.
• A primary pollutant is a type of pollutant that is emitted directly to the environment from sources such as cars, coal-fired power plants, natural gas power plants, biomass burning, forest fires, volcanoes, etc.
• Secondary pollutants are those pollutants formed by reacting with the primary pollutant sources to form a new pollutant.

Examples of primary and secondary air pollutants:

Explanation:

Option 1) HNO₃ - CORRECT

It is a secondary air pollutant as nitric oxides when dissolved in water, produce nitric acid and produce acid rain.
This option is correct.

Option 2) Cl₂ - INCORRECT

• It is known to deplete the ozone layer without reacting with any compound. It is a primary pollutant.
• It is not a secondary pollutant.
• This option is incorrect.

Option 3) NO₂ - INCORRECT

• Combustion of coal and oil produces thermal and fuel nitrogen oxides, which are primary pollutants.
• This option is incorrect.

So, the correct answer is Option  1)  HNO₃

The correct answer is Above 65db

Concept:

Sound:

• Sound is a form of energy produced by vibrations that travel through a medium, such as air, water, or solids, in the form of waves. These vibrations cause changes in air pressure, which our ears detect and perceive as sound. Sound waves can vary in frequency (pitch) and amplitude (loudness), giving rise to different auditory sensations.
• The unit used to measure sound is the decibel (dB). Decibels are a logarithmic unit that quantifies the intensity or level of sound relative to a reference level. 

Explanation:

According to the World Health Organization (WHO), noise above 65 decibels (dB) is considered noise pollution. Prolonged exposure to noise levels above this threshold can have adverse effects on human health, including hearing loss, sleep disturbances, cardiovascular diseases, cognitive impairment, and stress-related disorders. Therefore, controlling and reducing noise pollution is essential for protecting public health and well-being.

Thus it concludes that, according to the World Health Organization (WHO), noise above 65 (dB) is defined as noise pollution. 

Concept:

• A device that uses basic redox reactions to reduce the pollutants emitted from vehicles is known as the catalytic converter.
• It helps in converting the harmful pollutants produced by the car engine into less harmful gases. It uses metallic catalysts to promote the reactions at low temperatures.

• The catalytic converter looks like a large metal box located on the underside of a vehicle. There are two pipes coming out of it.

• These two pipes and the catalyst are used by the converter during the process of making the gases safe to be expelled into the environment.

• From the “input” pipe connected to the engine of a vehicle gases are brought inside.

• After that gases are blown over the catalyst, which causes a chemical reaction that breaks apart the pollutants.

• Through the second pipe the less harmful gases now travel, or the “output,” that is connected to a car’s tailpipe.

• When the exhaust from the automobile passes through the catalytic converter it oxidizes carbon monoxide to carbon dioxide, oxidizes hydrocarbons to carbon dioxide and water and it converts NO_x to nitrogen by reduction.

Explanation:

• It uses metallic catalysts to promote the reactions at low temperatures.
• Platinum acts as an active catalyst and is used as a reduction as well as an oxidation catalyst.
• Rhodium acts as a reduction catalyst while Palladium acts as an oxidation catalyst.
• Chemical reactions occur on these catalysts and after that harmless gases are passed out into the atmosphere from the automobile.
• The precious metals Platinum-palladium and rhodium are mainly used as the catalytic converter.
• From the above points we can see that:
  • Option 1) Palladium, Molybdenum and Copper- INCORRECT
  • Option 2) Platinum, Aluminium and rhodium - INCORRECT
  • Option 3) Platinum, Sodium, and rhodium - INCORRECT
  • Option 4) Platinum-palladium and rhodium - CORRECT

The correct answer is Hertz

Explanation:-

• Frequency is denoted in units called Hertz (Hz).
• Hertz represents the number of cycles or oscillations per second. It is named after the German physicist Heinrich Hertz, who made significant contributions to the study of electromagnetism and the discovery of radio waves.
• In the context of sound, frequency represents the pitch of the sound, with higher frequencies corresponding to higher-pitched sounds and lower frequencies corresponding to lower-pitched sounds.
• In other fields such as physics and electronics, frequency is used to describe the rate of occurrence of periodic events or vibrations.

Additional InformationDecibel (dB):

• Decibel is the unit used to measure the intensity or amplitude of sound. It is a logarithmic scale that quantifies the relative loudness of a sound compared to a reference level.
• Decibels are commonly used in acoustics and sound engineering to describe the loudness of sounds across a wide range of frequencies.

Nanometer (nm):

• Nanometer is a unit of length equal to one billionth of a meter. It is commonly used to measure wavelengths, particularly in the fields of optics, photonics, and nanotechnology.
• In the context of electromagnetic waves, including light, radio waves, and X-rays, the wavelength represents the distance between successive peaks or troughs of the wave.

Sone:

• Sone is a unit used to measure the subjective loudness of sound as perceived by the human ear.
• Unlike decibels, which represent the physical intensity of sound waves, sones take into account the psychoacoustic factors that influence how humans perceive sound.
• The sone scale is based on empirical studies of human perception of loudness.
• One sone is defined as the loudness of a 1 kHz tone at 40 dB SPL (sound pressure level) as perceived by the average listener.
• Higher sone values indicate greater perceived loudness, while lower sone values indicate quieter sounds.

Conclusion:- Frequency is denoted as Hertz.

The correct answer is CFC (Chlorofluorocarbons)
Explanation:

• CFCs (Chlorofluorocarbons) are released from the refrigerator industry. 
• CFCs were commonly used as refrigerants in air conditioning systems, refrigerators, and other cooling devices.
• However, they have been found to have a detrimental effect on the ozone layer in the Earth's stratosphere, contributing to ozone depletion.
• Due to their harmful environmental impact, the use of CFCs has been heavily regulated and phased out in many countries under the Montreal Protocol, an international treaty aimed at protecting the ozone layer.
• Manufacturers have transitioned to using alternative refrigerants that have lower ozone-depleting potential and reduced environmental impact.

The correct answer is Contamination is caused by the entry of germs into drinking water or edible foods.

Key Points

• Contamination of water and food means when water gets unfit for drinking and food to eat because of some impurity.
• Foods that are spoiled or tainted because they either contain microorganisms, such as bacteria or parasites, or toxic substances that make them unfit for consumption.
• A food contaminant can be biological, chemical or physical.

Additional Information

• Water can be contaminated in several ways.
  • It can contain microorganisms like bacteria and parasites that get in the water from human or animal faeces.
  • It can contain chemicals from industrial waste or from spraying crops. 
  • Various minerals such as lead or mercury can enter the water supply, sometimes from natural deposits underground, or more often from improper disposal.
• There are many cases of banned pesticides or carcinogens found in foods.
  • In India, soft drinks were found contaminated with high levels of pesticides and insecticides, including lindane, DDT, malathion and chlorpyrifos.
  • Formaldehyde, a carcinogen, was frequently found in the common Vietnamese dish, 
  • The 2005 Indonesia food scare, where carcinogenic formaldehyde was found to be added as a preservative to noodles, tofu, salted fish, and meatballs.
  • In 2008 Chinese milk scandal, melamine was discovered to have been added to milk and infant formula which caused 54,000 babies to be sent to the hospital. Six babies died because of kidney stones related to the contaminant.

The correct answer is Contamination is caused by the entry of germs into drinking water or edible foods.

Key Points

• Contamination of water and food means when water gets unfit for drinking and food to eat because of some impurity.
• Foods that are spoiled or tainted because they either contain microorganisms, such as bacteria or parasites, or toxic substances that make them unfit for consumption.
• A food contaminant can be biological, chemical or physical.

Additional Information

• Water can be contaminated in several ways.
  • It can contain microorganisms like bacteria and parasites that get in the water from human or animal faeces.
  • It can contain chemicals from industrial waste or from spraying crops. 
  • Various minerals such as lead or mercury can enter the water supply, sometimes from natural deposits underground, or more often from improper disposal.
• There are many cases of banned pesticides or carcinogens found in foods.
  • In India, soft drinks were found contaminated with high levels of pesticides and insecticides, including lindane, DDT, malathion and chlorpyrifos.
  • Formaldehyde, a carcinogen, was frequently found in the common Vietnamese dish, 
  • The 2005 Indonesia food scare, where carcinogenic formaldehyde was found to be added as a preservative to noodles, tofu, salted fish, and meatballs.
  • In 2008 Chinese milk scandal, melamine was discovered to have been added to milk and infant formula which caused 54,000 babies to be sent to the hospital. Six babies died because of kidney stones related to the contaminant.

Concept:

• Air pollution is the adulteration of air due to the presence of substances in the atmosphere that are harmful to the health of living beings by causing various diseases or causes damage to the climate.
• Particles less than 10 μm in diameter suspended in the atmospheric environment are known as suspended particular matter (SPM).
• They are the major cause of pollution in metropolitan cities that arises in the air from the combustion of wood, industries, coals, fuel burning, etc.
• Sulfur oxides, oxides of nitrogen, and carbon monoxide cause pollution but their quantities are less than that of suspended particulate matter.

Explanation:

Option 1: Oxides of sulfur - INCORRECT

• Sulfur dioxide combines with water and air to form sulfuric acid, which is the main component of acid rain. This is not the major cause of pollution in metro cities.
• So, this option is not correct. 

Option 2: Suspended particular matter (SPM) - CORRECT

• Particles less than 10 μm in diameter suspended in the atmospheric environment are known as Suspended particulate matter (SPM).

• The sum of all solid and liquid particles suspended in air is known as particulate matter. Many of which are hazardous particles.
• This includes both organic and inorganic particles, such as dust, pollen, soot, smoke, and liquid droplets.
• It is the major cause of pollution in metro cities and is suspended into the air.
• So, this option is correct. 

Option 3: Carbon dioxide and carbon monoxide - INCORRECT

• An increase in the amount of carbon dioxide in the atmosphere causes pollution.
• Carbon monoxide affects the number of greenhouse gases, which are linked to climate change and global warming when it is emitted into the atmosphere.
• But, this is not the major cause of pollution in metro cities.
• So, this option is not correct. 

Option 4: Oxides of nitrogen - INCORRECT

• Oxides of nitrogen pollution are emitted by automobiles, trucks, and various non-road vehicles (e.g., construction equipment, boats, etc.)
• But, this is not the major cause of pollution in metro cities.
• So, this option is not correct. 

So, the correct answer is Option (2).