Learn Environmental Chemistry MCQ questions & answers in Inorganic Chemistry are available for students perparing for IIT-JEE, NEET, Engineering and Medical Enternace exam.
51.
Addition of phosphate fertilisers to water bodies causes :
A
Increase in amount of dissolved oxygen in water
B
Deposition of calcium phosphate
C
Increase in fish population
D
Enhanced growth of algae
Answer :
Enhanced growth of algae
No explanation is given for this question. Let's discuss the answer together.
52.
Freons are not recommended to be used in refrigerators because they
A
cause global warming
B
cause acid rain
C
cause depletion of ozone layer
D
cause very less cooling
Answer :
cause depletion of ozone layer
Freons are $$CFCs$$ which cause ozone layer depletion.
53.
Water sample is reported to be highly polluted if $$BOD$$ ( Biological Oxygen Demand ) value of sample becomes
A
more than $$17\,ppm.$$
B
equal to $$10\,ppm.$$
C
equal to $$5\,ppm.$$
D
less than $$5\,ppm.$$
Answer :
more than $$17\,ppm.$$
Water sample is reported to be highly polluted if $$BOD$$ value of sample is more than $$17\,ppm.$$
54.
$$BOD$$ is connected with
A
microbes and organic matter.
B
organic matter.
C
microbes.
D
None of the above
Answer :
microbes and organic matter.
$$BOD$$ is connected with microbes and organic matter
55.
Acid rain is produced by
A
excessive release of $$CO$$ in air
B
excessive release of $$S{O_2}$$ and $${H_2}S$$ in air
C
excessive release of $$N{O_2}$$ and $$S{O_2}$$ in air
D
excessive release of $$N{H_3}$$ and $$C{O_2}$$ in air
Answer :
excessive release of $$N{O_2}$$ and $$S{O_2}$$ in air
Acid rain is produced by excess of $$N{O_2}$$ and $$S{O_2}$$ released from burning of fossil fuels.
$$2S{O_2} + {O_2} \to 2S{O_3};$$ $$S{O_3} + {H_2}O \to {H_2}S{O_4}$$
$$4N{O_2} + {O_2} + 2{H_2}O \to 4HN{O_3}$$
56.
Which of the following conditions show the polluted environment?
(i) $$pH$$ of rain water is 5.6.
(ii) Amount of carbon dioxide in the atmosphere is $$0.03\% .$$
(iii) Biochemical oxygen demand is $$10\,ppm.$$
(iv) Eutrophication
A
(i) and (ii) only
B
(ii) and (iii) only
C
(iii) and (iv) only
D
(i), (ii), (iii) and (iv)
Answer :
(iii) and (iv) only
$$BOD$$ value more than $$5\,ppm$$ shows water is polluted.
The process in which nutrient enriched water bodies support a dense plant population, which kills aquatic life by depriving them of oxygen and results in subsequent loss of biodiversity is known as eutrophication.
57.
Which of the following statements is not true about classical smog?
A
Its main components are produced by the action of sunlight on emissions of automobiles and factories.
B
Produced in cold and humid climate.
C
It contains compounds of reducing nature.
D
It contains smoke, fog and sulphur dioxide.
Answer :
Its main components are produced by the action of sunlight on emissions of automobiles and factories.
The main components of photochemical smog are produced by the action of sunlight on emissions of automobiles and factories.
58.
Which of the following free radicals is responsible for causing break down of ozone into oxygen due to us of $$CFCs?$$
A
$$\mathop O\limits^ \bullet $$
B
$$\mathop C\limits^ \bullet l$$
C
$$\mathop C\limits^ \bullet {H_3}$$
D
$$\mathop O\limits^ \bullet H$$
Answer :
$$\mathop C\limits^ \bullet l$$
\[C{{F}_{2}}C{{l}_{2}}\xrightarrow{UV}\overset{\bullet }{\mathop{C}}\,l+\overset{\bullet }{\mathop{C}}\,{{F}_{2}}Cl\]
$$\mathop C\limits^ \bullet l + {O_3} \to Cl\mathop O\limits^ \bullet + {O_2},$$ $$Cl\mathop O\limits^ \bullet + O \to \mathop C\limits^ \bullet l + {O_2}$$
The chlorine radicals are continuously regenerated and cause the break down of ozone.
59.
Which of the following statement$$(s)$$ is/are correct ?
(i) Classical smog is a mixture of smoke, fog and sulphur dioxide.
(ii) Classical smog is also called oxidising smog
(iii) Hydrocarbons, $$N{O_2}$$ and $$PAN$$ are components of photochemical smog.
A
(i) and (iii)
B
(i) and (ii)
C
(iii) only
D
(i), (ii) and (iii)
Answer :
(i) and (iii)
Classical smog is also called reducing smog.
60.
Carbon monoxide is harmful to human beings as it
A
is carcinogenic
B
is antagonistic to $$C{O_2}$$
C
has higher affinity for haemoglobin as compared to oxygen
D
is destructive to $$C{O_2}$$
Answer :
has higher affinity for haemoglobin as compared to oxygen
Carbon monoxide has higher affinity for haemoglobin as compared to oxygen. It forms carboxy- haemoglobin which reduces the oxygen carrying capacity of blood which causes anoxia and lead to coma and death.