Environmental Chemistry

JEE Chemistry · 92 questions · Page 2 of 10 · Click an option or "Show Solution" to reveal answer

Q11

The molecule that has minimum /no role in the formation of photochemical smog, is :

A CH2 = O

B O3

C N2

D NO

Correct Answer

Option C

Solution

Photochemical smog is produced when ultraviolet light from sun reacts with NO , O3 and hydrocarbon in atmosphere.

Q12

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

Correct Answer

Option C

Solution

NOTE : Ozone layer acts as a shield and does not allow ultraviolet radiation from sun to reach earth.

It does not prevent infra-red radiation from sun to reach earth.

Thus option

(c)

is wrong statement and so it is the correct answer.

Q13

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

Correct Answer

Option B

Solution

When Mn present in water with concentration 0.05 ppm or more than this then the water is unsuitable for drinking.

Here given concentration for Mn is 5.0, which is grater than 0.05 that is why it is Mn makes water unsuitable for drinking.

For other metal water is suitable for drinking when concentration for Fe = 0.2 ppm and for Cu = 3.0 ppm and for Zn = 5.0 ppm.

Q14

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

Correct Answer

Option D

Solution

Classical smog occurs in a cool humid climate, it is a mixture of smoke, fog, and SO2. It is known as reducing smog.

Q15

Which one of the following gases is reported to retard photosynthesis?

A CO

B CFCs

C CO2

D NO2

Correct Answer

Option D

Solution

According to NCERT only NO2 from the given options can retard the photosynthesis process in plants.

Q16

Which one of the following is used to remove most of plutonium from spent nuclear fuel?

A ClF3

B O2F2

C I2O5

D BrO3

Correct Answer

Option B

Solution

O2F2 oxidizes plutonium to PuF6 and the reaction is used in removing plutonium as PuF6 from spent nuclear fuel.

Q17

BOD values (in ppm) for clean water (A) and polluted water (B) are expected respectively :

A A > 50, B < 27

B A > 25, B < 17

C A < 5, B > 17

D A > 15, B > 47

Correct Answer

Option C

Solution

BOD values of clean water (A) is less than 5 ppm So, A < 5 BOD values of polluted water (B) is greater than 17 ppm So, B > 17 So, Ans. is (c)

Q18

Polar stratospheric clouds facilitate the formation of :

A ClONO2

B HOCl

C ClO

D CH4

Correct Answer

Option B

Solution

Polar stratospheric clouds provide surface on which hydrolysis of $\mathrm{ClONO}_2$ takes place to form $\mathrm{HOCl}$ (Hypochlorous acid)

\mathrm{ClONO}_2(\mathrm{~g})+\mathrm{H}_2 \mathrm{O}(\mathrm{g}) \rightarrow \mathrm{HOCl}(\mathrm{g})+\mathrm{HNO}_3(\mathrm{~g})

Q19

The eutrophication of water body results in :

A loss of Biodiversity.

B breakdown of organic matter.

C increase in biodiversity.

D decrease in BOD.

Correct Answer

Option A

Solution

Eutrophication is the process in which nutrient enriched water bodies support a dense plant population, which kills animal life by depriving it of oxygen and results in subsequent loss of biodiversity.

Q20

Match List I with List II .tg .tg LIST I LIST II A. Nitrogen oxides in air I. Eutrophication B. Methane in air II. pH of rain water becomes 5.6 C. Carbon dioxide III. Global warming D. Phosphate fertilisers in water IV. Acid rain Choose the correct answer from the options given below :

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

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

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

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

Correct Answer

Option D

Solution

Let's match the items in List I with the items in List II: A.

Nitrogen oxides in air - These are responsible for acid rain.

So, A-IV.

Methane in air - Methane is a greenhouse gas, contributing to global warming.

So, B-III.

Carbon dioxide - Normal rain water has a pH of 5.6 (slightly acidic).

This is because it is exposed to the carbon dioxide in the atmosphere.

So, C-II.

Phosphate fertilizers in water - These contribute to eutrophication.

So, D-I.

Therefore, the correct answer is: A-IV, B-III, C-II, D-I

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