Learn Environmental Chemistry MCQ questions & answers in Inorganic Chemistry are available for students perparing for IIT-JEE, NEET, Engineering and Medical Enternace exam.
61.
Photochemical smog occurs in warm, dry and sunny climate. One of the following is not amongst the components of photochemical smog, identify it.
A
$$N{O_2}$$
B
$${O_3}$$
C
$$S{O_2}$$
D
$${\text{Unsaturated hydrocarbon}}$$
Answer :
$$S{O_2}$$
$$S{O_2}$$ is the component of classical smog ( i.e.; reducing smog ) while unsaturated hydrocarbons, nitrogen oxides and ozone are the components of photochemical smog ( i.e.; oxidising smog ).
62.
Which causes death of fishes in water bodies polluted by sewage ?
A
Foul smell
B
Pathogens
C
Clogging of gills by silt
D
Decrease in $$D.O.$$
Answer :
Decrease in $$D.O.$$
Decrease in $$D.O.$$ causes death of fish
63.
Which of the following is not regarded as a pollutant?
A
$$N{O_2}$$
B
$$C{O_2}$$
C
$$S{O_2}$$
D
$$CO$$
Answer :
$$C{O_2}$$
$$C{O_2}$$ present in normal concentration is not an air pollutant. However, when $$C{O_2}$$ level increases in atmosphere, it results in global warming.
64.
Organic matter is considered as a major source of water pollution caused by wastes of food, animal and human excreta, garbage etc. The excess of organic matter in water causes a threat to aquatic life because
A
the space available to aquatic life decreases
B
microorganisms consume dissolved oxygen to decompose organic matter
C
organic matter is swallowed by small animals
D
decomposition of organic matter increases the temperature of water
Answer :
microorganisms consume dissolved oxygen to decompose organic matter
If a lot of organic matter is decomposed, a lot of dissolved oxygen is consumed by microorganisms hence dissolved oxygen is no longer available for aquatic life.
65.
Which one of the following depletes ozone layer ?
A
$$CO$$
B
$$NO\,\,{\text{and freons}}$$
C
$$S{O_2}$$
D
$$C{O_2}$$
Answer :
$$NO\,\,{\text{and freons}}$$
$$NO$$ and freons are responsible for ozone layer depletion.
66.
Which of the following acts as a sink for $$CO?$$
A
Plants
B
Haemoglobin
C
Microorganisms present in the soil
D
Oceans
Answer :
Microorganisms present in the soil
$$CO$$ is converted into $$C{O_2}$$ by microorganism present in soil.
67.
Biological Oxygen Demand $$\left( {BOD} \right)$$ can be defined as,
A
the amount of oxygen required by bacteria to break down the organic matter of a sample of water
B
the amount of chemicals required to break down the organic matter of a sample of water
C
the amount of phosphate required to oxidise the organic matter of a sample of water
D
the amount of organic matter present in the given sample of water
Answer :
the amount of oxygen required by bacteria to break down the organic matter of a sample of water
The amount of $$BOD$$ in water is the measure of the amount of organic matter in water in terms of how much oxygen is required to break it down biologically.
68.
Which of the following statements about polar stratosphere clouds $$(PSCs)$$ is not correct ?
A
$$PSCs$$ do not react with chlorine nitrate and $$HCl.$$
B
Type $$I$$ clouds are formed at about $$ - {77^ \circ }C$$ and contain solid $$HN{O_3}.3{H_2}O.$$
C
Type $$II$$ clouds are formed at about $$ - {85^ \circ }C$$ and contain some ice.
D
A tight whirlpool of wind called Polar Vortex is formed which surrounds Antarctica.
Answer :
$$PSCs$$ do not react with chlorine nitrate and $$HCl.$$
$$PSCs$$ react with chlorine nitrate and $$HCl$$ to give $$HOCl$$ and $$C{l_2}.$$
69.
The zone which extends above troposphere up to 50 km above sea level and contains dinitrogen, dioxygen, ozone and little water vapour is called
A
exosphere
B
mesosphere
C
ionosphere
D
stratosphere
Answer :
stratosphere
No explanation is given for this question. Let's discuss the answer together.
70.
Which of the following is not an air pollutant?