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Environmental Chemistry

96 Questions Start JEE Mains Test
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2021 Q51 JEE Mains MCQ
14 Mar 2026
Reducing smog is a mixture of :
A.
Smoke, fog and O3
B.
Smoke, fog and N2O3
C.
Smoke, fog and CH2 = CH $-$ CHO
D.
Smoke, fog and SO2
2021 Q52 JEE Mains MCQ
14 Mar 2026
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
2021 Q53 JEE Mains MCQ
14 Mar 2026
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
2021 Q54 JEE Mains MCQ
14 Mar 2026
The presence of ozone in troposphere :
A.
protects us from greenhouse effect
B.
protects us from the UV radiation
C.
protects us from the X-ray radiation
D.
generates photochemical smog
2021 Q55 JEE Mains MCQ
14 Mar 2026
Given below are two statements :

Statement I : The pH of rain water is normally 5.6.

Statement II : If the pH of rain water drops below 5.6, it is called acid rain.

In the light of the above statements, choose the correct answer from the options given below :
A.
Both Statement I and Statement II are true.
B.
Both Statement I and Statement II are false.
C.
Statement I is true but Statement II is false.
D.
Statement I is false but Statement II is true.
2021 Q56 JEE Mains MCQ
14 Mar 2026
Given below are two statements :

Statement I : An allotrope of oxygen is an important intermediate in the formation of reducing smog.

Statement II : Gases such as oxides of nitrogen and sulphur present in troposphere contribute to the formation of photochemical smog.

In the light of the above statements, choose the correct answer from the options given below :
A.
Statement I is false but Statement II is true
B.
Both Statement I and Statement II are false
C.
Both Statement I and Statement II are true
D.
Statement I is true but Statement II is false
2021 Q57 JEE Mains MCQ
14 Mar 2026
Given below are two statements :

Statement I : The value of the parameter "Biochemical Oxygen Demand (BOD)" is important for survival of aquatic life.

Statement II : The optimum value of BOD is 6.5 ppm.

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.
Statement I is true but Statement II is false
C.
Both Statement I and Statement II are true
D.
Both Statement I and Statement II are false
2021 Q58 JEE Mains MCQ
14 Mar 2026
The gas released during anaerobic degradation of vegetation may lead to :
A.
Ozone hole
B.
Corrosion of metals
C.
Acid rain
D.
Global warming and cancer
2020 Q59 JEE Mains MCQ
14 Mar 2026
The presence of soluble fluoride ion upto 1 ppm concentration in drinking water, is :
A.
safe for teeth
B.
harmful to skin
C.
harmful for teeth
D.
harmful to bones
2020 Q60 JEE Mains MCQ
14 Mar 2026
The condition that indicates a polluted environment is :
A.
BOD value of 5 ppm
B.
eutrophication
C.
0.03% of CO2 in the atmosphere
D.
pH of rain water to be 5.6
2020 Q61 JEE Mains MCQ
14 Mar 2026
The processes of calcination and roasting in metallurgical industries, respectively, can Iead to :
A.
Global warming and photochemical smog
B.
Photochemical smog and ozone layer depletion
C.
Photochemical smog and global warming
D.
Global warming and acid rain
2020 Q62 JEE Mains MCQ
14 Mar 2026
The incorrect statement(s) among (a) – (d) regarding acid rain is (are) :

(a) It can corrode water pipes.
(b) It can damage structures made up of stone.
(c) It cannot cause respiratory ailments in animals.
(d) It is not harmful for trees
A.
(c) and (d)
B.
(a), (b) and (d)
C.
(c) only
D.
(a), (c) and (d)
2020 Q63 JEE Mains MCQ
14 Mar 2026
Thermal power plants can lead to :
A.
Ozone layer depletion
B.
Blue baby syndrome
C.
Eutrophication
D.
Acid rain
2020 Q64 JEE Mains MCQ
14 Mar 2026
The statement that is not true about ozone is :
A.
In the stratosphere, CFCs release chlorine free radicals (Cl) which reacts with O3 to give chlorine dioxide radicals
B.
It is a toxic gas and its reaction with NO gives NO2.
C.
In the atmosphere, it is depleted by CFCs
D.
In the stratosphere, it forms a protective shield against UV radiation
2020 Q65 JEE Mains MCQ
14 Mar 2026
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.
2020 Q66 JEE Mains MCQ
14 Mar 2026
Among the gases (a) – (e), the gases that cause greenhouse effect are :
(a) CO2
(b) H2O
(c) CFCs
(d) O2
(e) O3
A.
(a), (b), (c) and (d)
B.
(a) and (d)
C.
(a), (b), (c) and (e)
D.
(a), (c), (d) and (e)
2019 Q67 JEE Mains MCQ
14 Mar 2026
The primary pollutant that leads to photochemical smog is :
A.
acrolein
B.
ozone
C.
sulphur dioxide
D.
nitrogen oxides
2019 Q68 JEE Mains MCQ
14 Mar 2026
The correct set of species responsible for the photochemical smog is :
A.
NO, NO2, O3 and hydrocarbons
B.
N2, NO2 and hydrocarbons
C.
CO2, NO2, SO2 and hydrocarbons
D.
N2, O2, O3 and hydrocarbons
2019 Q69 JEE Mains MCQ
14 Mar 2026
Air pollution that occurs in sunlight is :
A.
oxidising smog
B.
reducing smog
C.
fog
D.
acid rain
2019 Q70 JEE Mains MCQ
14 Mar 2026
The regions of the atmosphere, where clouds form and where we live, respectively, are :
A.
Stratosphere and Stratosphere
B.
Stratosphere and Troposphere
C.
Troposphere and Stratosphere
D.
Troposphere and Troposphere
2019 Q71 JEE Mains MCQ
14 Mar 2026
The layer of atmosphere between 10 km to 50 km above the sea level is called as :
A.
mesosphere
B.
thermosphere
C.
troposphere
D.
stratosphere
2019 Q72 JEE Mains MCQ
14 Mar 2026
Excessive release of CO2 into the atomosphere results in :
A.
depletion of ozone
B.
polar vortex
C.
global warming
D.
formation of smog
2019 Q73 JEE Mains MCQ
14 Mar 2026
The maximum prescribed concentration of copper in drinking water is :
A.
3 ppm
B.
5 ppm
C.
0.5 ppm
D.
0.05 ppm
2019 Q74 JEE Mains MCQ
14 Mar 2026
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.
2019 Q75 JEE Mains MCQ
14 Mar 2026
Which is wrong with respect to our responsiblity as a human being to protect our environment?
A.
Restricting the use of vehicles
B.
Setting up compost tin in gardens.
C.
Avoiding the use of floodlighted facilities
D.
Using plastic bags.
2019 Q76 JEE Mains MCQ
14 Mar 2026
The compound that is NOT a common component of photochemical smog is :
A.
O3
B.
JEE Main 2019 (Online) 12th January Evening Slot Chemistry - Environmental Chemistry Question 76 English Option 2
C.
CH2 = CHCHO
D.
CF2Cl2
2019 Q77 JEE Mains MCQ
14 Mar 2026
The molecule that has minimum /no role in the formation of photochemical smog, is :
A.
CH2 = O
B.
O3
C.
N2
D.
NO
2019 Q78 JEE Mains MCQ
14 Mar 2026
Water samples with BOD values of 4 ppm and 18 ppm, respectively are :
A.
Clean and Highly polluted
B.
Highly polluted and Clean
C.
Highly polluted and Highly polluted
D.
Clean and Clean
2019 Q79 JEE Mains MCQ
14 Mar 2026
Taj Mahal is being slowly disfigured and discoloured. This is primarily due to :
A.
acid rain
B.
soil pollution
C.
global warming
D.
water pollution
2019 Q80 JEE Mains MCQ
14 Mar 2026
The higher concentration of which gas in air can cause stiffness of flower buds?
A.
CO2
B.
SO2
C.
NO2
D.
CO
2019 Q81 JEE Mains MCQ
14 Mar 2026
Peroxyacetyl nitrate (PAN), an eye irritant is produced by :
A.
classical smog
B.
acid rain
C.
photochemical smog
D.
organic waste
2019 Q82 JEE Mains MCQ
14 Mar 2026
The concentration of dissolved oxygen (DO) in cold water can go upto :
A.
14 ppm
B.
16 ppm
C.
8 ppm
D.
10 ppm
2019 Q83 JEE Mains MCQ
14 Mar 2026
The reaction that is NOT involved in the ozone layer depletion mechanism in the stratosphere is :
A.
$Cl\mathop O\limits^ \bullet \left( g \right) + O\left( g \right) \to \mathop C\limits^ \bullet l\left( g \right) + {O_2}(g)$
B.
$C{F_2}C{l_2}\left( g \right)\,\buildrel {uv} \over \longrightarrow \mathop {\,C}\limits^ \bullet l\left( g \right) + \mathop C\limits^ \bullet {F_2}Cl\left( g \right)$
C.
$C{H_4} + 2{O_3}\, \to \,3C{H_2} = O + 3{H_2}O$
D.
$HOCl\left( g \right)\,\buildrel {hv} \over \longrightarrow \,\mathop O\limits^ \bullet H\left( g \right) + \mathop C\limits^ \bullet l\left( g \right)$
2019 Q84 JEE Mains MCQ
14 Mar 2026
Water filled in two glasses A and B have BOD values of 10 and 20, respectively. The correct statement regarding them, is :
A.
B is more polluted than A.
B.
A is suitable for drinking, whereas B is not .
C.
Both A and B are suitable for dirnking
D.
A is more polluted than B.
2019 Q85 JEE Mains MCQ
14 Mar 2026
Which of the following conditions in drinking water causes methemoglobinemia?
A.
> 50 ppm of lead
B.
> 50 ppm of chloride
C.
> 50 ppm of nitrate
D.
> 100 ppm of sulphate
2019 Q86 JEE Mains MCQ
14 Mar 2026
A water sample has ppm level concentration of the following metals : Fe = 0.2; Mn = 5.0; Cu = 3.0; Zn = 5.0. The metal that makes the water sample unsuitable for drinking is :
A.
Cu
B.
Mn
C.
Fe
D.
Zn
2018 Q87 JEE Mains MCQ
14 Mar 2026
The recommended concentration of fluoride ion in drinking water is up to 1 ppm as fluoride ion is required to make teeth enamel harder by converting
[3Ca3 (PO4)2.Ca(OH)2] to
A.
[3{Ca(OH)2}. CaF2]
B.
[CaF2]
C.
[3(CaF2). Ca(OH)2]
D.
[3Ca3(PO4)2. CaF2]
2018 Q88 JEE Mains MCQ
14 Mar 2026
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.
2017 Q89 JEE Mains MCQ
14 Mar 2026
Which of the following is a set of greenhouse gases?
A.
CH4, O3, N2, SO2
B.
O3, N2, CO2, NO2
C.
O3, NO2, SO2, Cl2
D.
CO2, CH4, N2O, O3
2017 Q90 JEE Mains MCQ
14 Mar 2026
Identify the pollutant gases largely responsible for the discoloured and lustreless nature of marble of the Taj Mahal.
A.
O3 and CO2
B.
CO2 and NO2
C.
SO2 and NO2
D.
SO2 and O3
2017 Q91 JEE Mains MCQ
14 Mar 2026
A water sample has ppm level concentration of following anions
F- = 10; $SO_4^{2-}$ = 100; $NO_3^-$ = 50
The anion/anions that make/makes the water sample unsuitable for drinking is/are :
A.
both $SO_4^{2-}$ and $NO_3^-$
B.
only F-
C.
only $SO_4^{2-}$
D.
only $NO_3^-$
2016 Q92 JEE Mains MCQ
14 Mar 2026
Which one of the following substances used in dry cleaning is a better strategy to control environmental pollution?
A.
Tetrachloroethylene
B.
Carbon dioxide
C.
Sulphur dioxide
D.
Nitrogen dioxide
2016 Q93 JEE Mains MCQ
14 Mar 2026
BOD stands for :
A.
Biological Oxygen Demand
B.
Bacterial Oxidation Demand
C.
Biochemical Oxygen Demand
D.
Biochemical Oxidation Demand
2016 Q94 JEE Mains MCQ
14 Mar 2026
The concentration of fluoride, lead, nitrate and iron in a water sample from an underground lake was found to be 1000 ppb, 40 ppb, 100 ppm and 0.2 ppm, respectively. This water is unsuitable for drinking due to high concentration of :
A.
Lead
B.
Nitrate
C.
Iron
D.
Fluoride
2008 Q95 JEE Mains MCQ
14 Mar 2026
Identify the wrong statements in the following :
A.
Chlorofluorocarbons are responsible for ozone layer depletion
B.
Greenhouse effect is responsible for global warming
C.
Ozone layer does not permit infrared radiation from the sun to reach the earth
D.
Acid rains is mostly because of oxides of nitrogen and sulphur
2004 Q96 JEE Mains MCQ
14 Mar 2026
The smog is essentially caused by the presence of :
A.
O2 and O3c
B.
O3 and N2
C.
Oxides of sulphur and nitrogen
D.
O2 and N2