Environmental Chemistry

NEET Chemistry · 96 questions · Page 6 of 10 · Click an option or "Show Solution" to reveal answer

Q51

How can photochemical smog be controlled?

A By using catalytic convertors in the automobiles/industry.

B By complete combustion of fuel.

C By using tall chimneys.

D By using catalyst.

Correct Answer

Option A

Solution

Option A, By using catalytic converters in the automobiles/industry, is the most appropriate answer to control photochemical smog.Photochemical smog is a type of air pollution that forms in urban areas when pollutants from automobile and industrial emissions, such as nitrogen oxides (NOx) and volatile organic compounds (VOCs), react in the presence of sunlight.Catalytic converters are devices that are installed in the exhaust systems of automobiles and in some industrial processes to remove pollutants from exhaust gases.

They work by using a catalyst to convert harmful pollutants, such as NOx and VOCs, into less harmful substances before they are released into the atmosphere.

This can significantly reduce the formation of photochemical smog.Option B, By complete combustion of fuel, is not a complete or sufficient solution to control photochemical smog.

Complete combustion of fuel, which refers to the complete oxidation of the fuel to produce carbon dioxide and water, can reduce the amount of unburned hydrocarbons and carbon monoxide in the exhaust gases.However, even with complete combustion, other pollutants, such as nitrogen oxides (NOx), can still be produced and contribute to the formation of photochemical smog.

NOx emissions are a result of high temperatures and pressures in the combustion process and are not easily prevented through complete combustion alone.Additionally, while complete combustion can reduce the amount of certain pollutants, it does not address other sources of pollution, such as industrial emissions, that can contribute to the formation of photochemical smog.Therefore, while complete combustion can be an important step in reducing emissions and controlling photochemical smog, it is not a sufficient solution on its own and must be combined with other methods, such as the use of catalytic converters, to effectively address this issue.Option C, using tall chimneys, is not a direct way to control photochemical smog.

Tall chimneys can help to disperse pollutants into the atmosphere, but do not necessarily prevent their formation in the first place.Option D, By using a catalyst, is not a complete or sufficient solution to control photochemical smog.

While catalysts can be used to convert harmful pollutants into less harmful substances, they need to be part of a larger system, such as a catalytic converter, to effectively reduce emissions.Using a catalyst alone, without the proper design, engineering, and installation, is unlikely to be effective in controlling photochemical smog.

It is important to note that the goal is to reduce the overall emissions of pollutants, such as nitrogen oxides (NOx) and volatile organic compounds (VOCs), which are the precursors to photochemical smog.Therefore, while catalysts can be a useful tool in controlling photochemical smog, they must be used in combination with other methods, such as the use of catalytic converters in automobiles and industry, to be most effective.

Q52

Correct statement about smog is :

A NO

_2

is present in classical smog

B Both NO

_2

and SO

_2

are present in classical smog

C Photochemical smog has high concentration of oxidizing agents

D Classical smog also has high concentration of oxidizing agents

Correct Answer

Option C

Solution

Photochemical smog has high concentration of oxidising agents NO2 is produced from NO and O3 in the presence of sunlight Classical smog contain smoke, fog and SO2 and it is known as reducing smog, as chemically it is reducing mixture

Q53

Assertion : Ozone is destroyed by CFCs in the upper stratosphere. Reason : Ozone holes increase the amount of UV radiation the earth.

A Assertion and reason are both correct, and the reason is the correct explanation for the assertion.

B Assertion and reason are incorrect.

C Assertion and reason are correct but, the reason is not the explanation for the assertion

D Assertion is false, but the reason is correct.

Correct Answer

Option C

Solution

CFC’s are responsible for depletion of ozone layer.

When the ozone holes increases more UV rays will enter the earth.

So here both Assertion and reason are correct but reason is not the correct explanation for why CFC is destroying the ozone layer.

Q54

Given below are two statements : Statement I : Non-biodegradable wastes are generated by the thermal power plants. Statement II : Bio-degradable detergents leads to eutrophication. In the light of the above statements, choose the most appropriate answer from the options given below :

A Statement I is false but statement II is true.

B Both statement I and statement II are true.

C Both statement I and statement II are false.

D Statement I is true but statement is false.

Correct Answer

Option B

Solution

Non-biodegradable wastes are generated by thermal power which produce fly ash.

Nowadays most of the detergents available are biodegradable.

The bacteria responsible for degrading biodegradable detergent feed on it and grow rapidly.

While growing, they may use up all the oxygen dissolved in water which cause Eutrophication.

Q55

The higher concentration of which gas in air can cause stiffness of flower buds?

A CO2

B SO2

C NO2

D CO

Correct Answer

Option B

Solution

Due to acid rain in plants high concentration of SO2 makes the flower buds stiff and makes them fall.

Q56

The gas 'A' is having very low reactivity reaches to stratosphere. It is non-toxic and non-flammable but dissociated by UV-radiations in stratosphere. The intermediates formed initially from the gas 'A' are :

Cl\mathop O\limits^ \bullet + \mathop C\limits^ \bullet {F_2}Cl

Cl\mathop O\limits^ \bullet + C\mathop {{H_3}}\limits^ \bullet

\mathop C\limits^ \bullet {H_3} + C\mathop {{F_2}}\limits^ \bullet Cl

\mathop C\limits^ \bullet l + C\mathop {{F_2}}\limits^ \bullet Cl

Correct Answer

Option D

Solution

In stratosphere CFCs get broken down by powerful UV radiations releasing

C{l^ \bullet }

C{F_2}C{l_2}(g)\overset{{U.V.}}\longrightarrow C{l^ \bullet }(g) + {}^ \bullet C{F_2}Cl(g)

Q57

Biochemical Oxygen Demand (BOD) value can be a measure of water pollution caused by the organic matter. Which of the following statements is correct ?

A Aerobic bacteria decrease the BOD value.

B Anaerobic bacteria increase the BOD value.

C Clean water has BOD value higher than 10 ppm.

D Polluted water has BOD value higher than 10 ppm.

Correct Answer

Option D

Solution

Aerobic bacteria decreases the BOD value and aerobic bacteria increase the BOD value.

Clear water has BOD value less than 5 ppm.

Polluted water has BOD value higher than 10 ppm.

Q58

Match with . .tg .tg Pollutant Disease/sickness

List - I		List - II
(A)	Sulphate (>500 ppm)	(I)	Methemoglobinemia
(B)	Nitrate (>50 ppm)	(II)	Brown mottling of teeth
(C)	Lead (>50 ppb)	(III)	Laxative effect
(D)	Fluoride (>2 ppm)	(IV)	Kidney damage

A A-IV, B-I, C-II, D-III

B A-III, B-I, C-IV, D-II

C A-II, B-IV, C-I, D-III

D A-II, B-IV, C-III, D-I

Correct Answer

Option B

Solution

Sulphate (>500 ppm) - Causes Laxative effect that leads to dehydration B.

Nitrate (>50 ppm) - Causes Methemoglobinemia, skin appears blue C.

Lead (> 50 ppb) – It damage kidney and RBC D.

Fluoride (>2 ppm) – It Causes Brown mottling of teeth

Q59

The statements that are TRUE : (A) Methane leads to both global warming and photochemical smog (B) Methane is generated from paddy fields (C) Methane is a stronger global warming gas than CO2 (D) Methane is a part of reducing smog Choose the most appropriate answer from the options given below :

A (A), (B), (C) only

B (A) and (B) only

C (B), (C), (D) only

D (A), (B), (D) only

Correct Answer

Option A

Solution

CH4 causes global warming and also a constituent of photochemical smog.

It is a part of oxidising smog.

CH4 is generated from paddy fields.

Due to high heat capacity, CH4 is a stronger global warming causing gas than CO2.

Q60

Correct statement is :

A An average human being consumes more food than air

B An average human being consumes 100 times more air than food

C An average human being consumes nearly 15 times more air than food

D An average human being consumes equal amount of food and air

Correct Answer

Option C

Solution

The correct statement is An average human being consumes nearly 15 times more air than food.

This is because humans need to breathe in a certain amount of air to supply oxygen to the body and release carbon dioxide, which is produced by cellular respiration.

On the other hand, the amount of food an average human consumes is much less than the amount of air, even though it is also essential for providing energy, nutrients, and other vital substances to the body.

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