Environmental Chemistry — Page 3 | JEE Chemistry

Q21

Match with .tg .tg Industry Waste Generated

List - I		List - II
(A)	Steel plants	(I)	Gypsum
(B)	Thermal power plants	(II)	Fly ash
(C)	Fertilizer industries	(III)	Slag
(D)	Paper mills	(IV)	Bio-degradable wastes

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

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

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

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

Correct Answer

Option A

Solution

A - Steel plants : They generate waste in the form of slag (III), which is a by-product of the smelting process used in steel production.

B - Thermal power plants : These plants generate fly ash (II) as a by-product of coal combustion.

C - Fertilizer industries : The manufacture of phosphate fertilizers can produce gypsum (I) as a waste product.

D - Paper mills : They generate bio-degradable wastes (IV) as a result of the pulp and papermaking processes.

Therefore, the correct option is A : (A)-(III), (B)-(II), (C)-(I), (D)-(IV).

Q22

Match List I with List II: .tg .tg LIST I (Species) LIST II (Maximum allowed concentration in ppm in drinking water) A.

\mathrm{F^-}

I. < 50 ppm B.

\mathrm{SO_4^{2-}}

II. < 5 ppm C.

\mathrm{NO_3^-}

III. < 2 ppm D.

\mathrm{Zn}

IV. < 500 ppm Choose the correct answer from the options given below :

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

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

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

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

Correct Answer

Option D

Solution

Fluoride ( $F^-$ ) : High concentration of fluoride can lead to a condition known as fluorosis, affecting teeth and bones.

Hence, the WHO sets the upper limit for fluoride in drinking water to be 1.5 ppm.

This can be approximated to less than 2 ppm.

Therefore, $F^-$ (List I: A) corresponds to < 2 ppm (List II: III).

Sulfate ( $SO_4^{2-}$ ) : The standard concentration limit for sulphates in drinking water, according to WHO, is 500 ppm.

Hence, $SO_4^{2-}$ (List I: B) matches with < 500 ppm (List II: IV).

Nitrate ( $NO_3^-$ ) : An excess of nitrate in drinking water can lead to health conditions such as methemoglobinemia.

The safe limit, according to the WHO, is 50 ppm.

Hence, $NO_3^-$ (List I: C) corresponds to < 50 ppm (List II: I).

Zinc (Zn) : Zinc is an essential nutrient, but excessive amounts in drinking water can be harmful.

The standard limit for zinc in drinking water is 5 ppm.

So, Zn (List I: D) corresponds to < 5 ppm (List II: II).

Q23

The delicate balance of

\mathrm{CO}_{2}

and

\mathrm{O}_{2}

is NOT disturbed by :

A Burning of Coal

B Burning of petroleum

C Respiration

D Deforestation

Correct Answer

Option C

Solution

The delicate balance of $\mathrm{CO}_2$ and $\mathrm{O}_2$ is disturbed by the burning of coal (Option A), the burning of petroleum (Option B), and deforestation (Option D).

These activities contribute to the increase in atmospheric $\mathrm{CO}_2$ levels, which can lead to global warming and climate change.

However, respiration (Option C) does not disturb the delicate balance of $\mathrm{CO}_2$ and $\mathrm{O}_2$ .

During respiration, organisms including humans and animals consume $\mathrm{O}_2$ and produce $\mathrm{CO}_2$ as a byproduct.

This $\mathrm{CO}_2$ can be utilized by plants during photosynthesis to produce $\mathrm{O}_2$ , thus maintaining a balance between $\mathrm{CO}_2$ and $\mathrm{O}_2$ levels in the atmosphere.

Q24

Which of the following statement(s) is (are) incorrect reason for eutrophication? (A) excess usage of fertilisers (B) excess usage of detergents (C) dense plant population in water bodies (D) lack of nutrients in water bodies that prevent plant growth Choose the most appropriate answer from the options given below :

A (A) Only

B (B) and (D) only

C (C) only

D (D) only

Correct Answer

Option D

Solution

Nutrient enriched water bodies support dense plant populations.

This is because of the excess usage of fertilizers and detergents.

This process is known as eutrophication.

Q25

The type of pollution that gets increased during the day time and in the presence of O3 is :

A Oxidising smog

B Global warming

C Acid rain

D Reducing smog

Correct Answer

Option A

Solution

Photochemical smog occurs in warm, dry, and sunny climates.

It is also called oxidizing smog.

The main components of photochemical smog are ozone, nitric oxide, acrolein, formaldehyde, and PAN.

Q26

Given below are two statements: Statement I : The non bio-degradable fly ash and slag from steel industry can be used by cement industry. Statement II : The fuel obtained from plastic waste is lead free. In the light of the above statements, choose the most appropriate answer from the options given below :

A Both Statement I and Statement II are correct

B Both Statement I and Statement II are incorrect

C Statement I is correct but Statement II is incorrect

D Statement I is incorrect but Statement II is correct

Correct Answer

Option A

Solution

Both Statement are correct. - Fuel obtained from plastic waste has high octane rating.

It contain no lead and is known as "green fuel". - The non bio-degradable fly ash and slag from steel industry can be used by cement industry.

Q27

Excessive release of CO2 into the atomosphere results in :

A depletion of ozone

B polar vortex

C global warming

D formation of smog

Correct Answer

Option C

Solution

CO2 causes global warming.

Q28

The green house gas/es is (are) : (A) Carbon dioxide (B) Oxygen (C) Water vapour (D) Methane Choose the most appropriate answer from the options given below :

A (A) and (C) only

B (A) and (B) only

C (A), (C) and (D) only

D (A) only

Correct Answer

Option C

Solution

Greenhouse gases are CO2, CH4, Water vapour, Nitrous oxide, CFCs and ozone.

Q29

Which of these reactions is not a part of breakdown of ozone in stratosphere?

A

\mathrm{C{F_2}C{l_2}(g)\overset{{uv}}\longrightarrow \mathop C\limits^ \bullet l(g) + \mathop C\limits^ \bullet {F_2}Cl(g)}

B

\mathrm{C\mathop l\limits^ \bullet (g) + {O_3}(g)\overset{{}}\longrightarrow Cl\mathop O\limits^ \bullet (g) + {O_2}(g)}

C

\mathrm{2Cl\mathop O\limits^ \bullet \overset{{}}\longrightarrow Cl{O_2}(g) + C\mathop l\limits^ \bullet (g)}

D

\mathrm{Cl\mathop O\limits^ \bullet (g) + O(g)\overset{{}}\longrightarrow C\mathop l\limits^ \bullet (g) + {O_2}(g)}

Correct Answer

Option C

Solution

The breakdown of ozone in the stratosphere largely involves a series of reactions often initiated by free radicals, such as chlorine (Cl), bromine (Br), or nitric oxide (NO) radicals.

In particular, chlorine atoms, which can come from substances like chlorofluorocarbons (CFCs), can catalyze the destruction of ozone.

The first three reactions listed are all part of the ozone breakdown process: Option A: This is the photodissociation of a chlorofluorocarbon, which releases a chlorine atom (a free radical) that can participate in ozone destruction.

\mathrm{CF_2Cl_2(g) \xrightarrow{uv} Cl(g) + CF_2Cl(g)}

Option B: This reaction shows a chlorine atom catalyzing the destruction of ozone, forming ClO and O2.

\mathrm{Cl(g) + O_3(g) \rightarrow ClO(g) + O_2(g)}

Option D: This reaction shows a ClO radical reacting with a single oxygen atom to regenerate the Cl radical and form O2.

The regenerated Cl radical can then go on to catalyze more ozone destruction, making this a catalytic cycle.

\mathrm{ClO(g) + O(g) \rightarrow Cl(g) + O_2(g)}

However, option C:

\mathrm{2ClO \rightarrow ClO_2 + Cl}

This reaction is not typically part of the ozone breakdown process.

Chlorine monoxide (ClO) radicals generally react with atomic oxygen (O), not with another ClO radical, to regenerate the chlorine radical and produce oxygen (O2).

The product of this reaction, ClO2, does not commonly appear in the standard ozone depletion mechanisms.

Q30

Biochemical Oxygen Demand (BOD) is the amount of oxygen required (in ppm) :

A for sustaining life in a water body.

B by anaerobic bacteria to breakdown inorganic waste present in a water body.

C for the photochemical breakdown of waste present in 1 m3 volume of a water body.

D by bacteria to break-down organic waste in a certain volume of a water sample.

Correct Answer

Option D

Solution

Biochemical oxygen demand (BOD) is amount of oxygen required by bacteria to break down organic waste in a certain volume of water sample.