Environmental Chemistry — Page 6 | JEE Chemistry

Q51

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.

Q52

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 :

A

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

B

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

C

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

D

\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)

Q53

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.

Q54

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

A.

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

Q55

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.

Q56

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.

Q57

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)\,\overset{{uv}}\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)\,\overset{{hv}}\longrightarrow \,\mathop O\limits^ \bullet H\left( g \right) + \mathop C\limits^ \bullet l\left( g \right)

Correct Answer

Option C

Solution

Ozone layer depletion mechanism occurs with Chlorofluorocarbons and involves chlorine radical.

In CH4, there is no Cl so it is not involved in the ozone layer depletion mechanism

Q58

Given below are two statements : Statement I : Chlorofluoro breakdown by radiation in the visible energy region and release chlorine gas in the atmosphere which then reacts with stratospheric ozone. Statement II : Atmospheric ozone reacts with nitric oxide to give nitrogen and oxygen gases, which add to the atmosphere. For the above statements choose the correct answer from the options given below :

A Statement I is incorrect but Statement II is true

B Both Statement I and II are false

C Statement I is correct but Statement II is false

D Both Statement I and II are correct

Correct Answer

Option B

Solution

Statement (1) CFCs are broken down by powerful UV radiation and releases chlorine free radical which reacts with ozone and start chain reaction.

C{F_2}C{l_2}_{(g)}\overset{{UV}}\longrightarrow \mathop C\limits^ \bullet {l_g} + \mathop C\limits^ \bullet {F_2}C{l_{(g)}}

\mathop C\limits^ \bullet {l_{(g)}} + {O_{3(g)}} \to \mathop C\limits^ \bullet l{O_{(g)}} + {O_{2(g)}}

\mathop C\limits^ \bullet l{O_{(g)}} + {O_{(g)}} \to \mathop C\limits^ \bullet {l_{(g)}} + {O_{2(g)}}

Statement (2) Atmosphere ozone reacts with nitric oxide to produce nitrogen dioxide and oxygen.

N{O_{(g)}} + {O_{3(g)}} \to N{O_{2(g)}} + {O_{2(g)}}

Q59

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.

Correct Answer

Option A

Solution

Two glasses ''A'' and ''B'' have BOD values 10 and ''20'', respectively.

Hence glasses ''B'' is more polluted than glasses ''A''.

Q60

The acid that is believed to be mainly responsible for the damage of Taj Mahal is :

A sulfuric acid.

B hydrofluoric acid.

C phosphoric acid.

D hydrochloric acid.

Correct Answer

Option A

Solution

CaCO3 + H2SO4 $\to$ CaSO4 + H2O + CO2 Industries like oil refinery releases SO2 which causes air pollution.

It reacts with water to form acid rain when SO2 mix with water it forms H2SO4 (Sulphuric acid).