MCQExams
0:0:1
CBSE
JEE
NTSE
NEET
Practice
Homework
×
CBSE Questions for Class 8 Chemistry Pollution Of Air And Water Quiz 4 - MCQExams.com
CBSE
Class 8 Chemistry
Pollution Of Air And Water
Quiz 4
When heat is reflected from the earth's surface and trapped in the atmosphere, this phenomenon is referred to as:
Report Question
0%
Global warming
0%
Ozone depletion
0%
The Greenhouse effect
0%
Thermal pollution
Explanation
Global warming
is the increase in the average temperature of the Earth's near-
surface air and the oceans because of the Greenhouse effect.
The greenhouse effect
is the process by which radiation from a planet's atmosphere warms the planet's surface to a temperature above what it would be without its atmosphere.
Thus option C is correct.
Which of the following statements is not true?
Report Question
0%
$$CO_2$$ is the best fire extinguisher.
0%
Global warming can cause acid rain.
0%
Burning of coal and diesel releases sulphur dioxide gas.
0%
LPG has higher calorific value than biogas.
Explanation
Global warming may cause glaciers to melt, which may lead to the
rise
in sea level and submerge
low-lying
areas but does not cause acid rain.
Fertilisers are a source of which types of pollution?
Report Question
0%
Soil and water pollution
0%
Air and sound pollution
0%
Only soil pollution
0%
Only air pollution
Explanation
Excessive use of fertilisers reduces the fertility of soil. Moreover, it also causes water pollution as the fertilisers are washed away into water bodies where they promote the growth of unwanted plants like weeds, apart from algae.
Which of the following is not a feature of potable water?
Report Question
0%
It must be clean, colourless and odourless.
0%
It must be free from bacteria.
0%
It must have excessive sodium, calcium, and magnesium as they give a special taste.
0%
It must contain dissolved oxygen and carbon dioxide.
Explanation
Potable water
is
water
that is fit for consumption by humans. Potable water is clean, colorless, odorless, bacteria-free, and has dissolved oxygen and carbon dioxide. It also has dissolved minerals like sodium, calcium, and magnesium. But if these minerals are present in excess amounts, they will cause health issues.
Hence, the correct option is $$\text{C}$$
Which method of water purification does not kill microorganisms?
Report Question
0%
Boiling
0%
Filtration
0%
Chlorination
0%
Distillation
Explanation
Filteration is a physical method that can only separate the pathogens and other contaminants from water but cannot kill microorganism.
Boiling kills all the pathogens at boiling temperature.
Chlorine kills pathogens such as bacteria and viruses by breaking the chemical bonds in their molecules.
Distillation relies on evaporation to purify water. Contaminated water is heated to form steam. The boiling process kills microorganisms such as bacteria and some viruses.
Environmental pollution can be controlled by:
Report Question
0%
spraying insecticides and pesticides
0%
open burning of tree stumps
0%
treating factory wastes before disposing them
0%
disposing hot water from power stations into the sea
Explanation
Environmental pollution can be controlled by treating factory wastes before disposing of them. So, if we treat wastewater before disposing of in a river, it will surely decrease the amount of dumped pollutants.
For example- Steel industries have a high concentration of cyanide in it, and it led to harmful effect. So, treatment is really necessary.
Hence, option C is correct.
Which water pollutant is incorrectly paired with the source?
Report Question
0%
Oil spill - ship
0%
Pesticide - oil palm plantation
0%
Sewage - large factory
0%
Smoke - farm
Explanation
Sewage comes from domestic waste or municipal waste from sewers, which does not include any industrial waste but only untreated sewage from local residential or commercial areas.
Oil spills can occur when petroleum products or fuel is leaked from ships or the tankers carried by them. Pesticides are used in farms and plantations, while smoke is released from automobiles, machines, factories, etc.
One of the causes of water pollution, is excessive use of ___________ and ___________ by the farmers:
Report Question
0%
manure, water
0%
fertilizers, pesticides
0%
fertilizers, seeds
0%
pesticides, seeds
Explanation
Excessive use of fertilisers and pesticides in fields can lead to their seepage into the ground and mixing with groundwater. They can also be washed away with rain and carried to water bodies, where they can contaminate the water and the aquatic animals, especially fish. Human beings consuming such contaminated fish might be fatally poisoned.
Also, rivers polluted by fertilisers allow the growth of algae that use dissolved oxygen in the water for their sustenance. This leads to oxygen deficiency in water, which can cause the death of other aquatic animals.
Carbon monoxide emitted by automobiles is poisonous because?
Report Question
0%
It changes $$O_2$$ to $$CO_2$$.
0%
It prevents breathing.
0%
It reduces oxygen carrying capacity of blood.
0%
It makes it difficult to see.
Explanation
Carbon monoxide mainly causes adverse effects in humans by combining with haemoglobin in the blood and preventing it from
carrying oxygen to the tissues.
So, option C is correct.
What is the main source of water pollution in India?
Report Question
0%
Discharge of untreated sewage
0%
Bathing
0%
Discharge of industrial waste
0%
Both A and C
Explanation
Sources of water pollution to rivers in India are done mainly by the industries and factories pouring untreated chemical waste in the rivers which are highly toxic in nature and another source is sewage waste from domestic households and municipalities goes directly to the river bodies causing major water pollution as it is highly pathogenic in nature.Bathing is not the major source as it forms a minor portion of the major sewage waste.
Monuments of marble can be destroyed by:
Report Question
0%
sulphur dioxide pollution
0%
carbon monoxide pollution
0%
pesticide pollution
0%
dust particles
Explanation
Sulphur dioxide fumes mix with air moisture or water vapor and come down as acid rain in the form of sulphuric acid. This acid rain can damage the marble tombs which are made up of calcium carbonate and its reaction with acid rain forms calcium sulfate which gives a yellowish color of acid to the marble. This gradually destroys the marble structure over a period of time.
Hence, option $$A$$ is correct.
Which of these is the major air pollutant in cities like Delhi and Kolkata?
Report Question
0%
Carbon monoxide
0%
Hydrocarbons
0%
Suspended particulate matter
0%
Oxides of nitrogen
Explanation
According to the air pollution data, the suspended particulate matter (SPM) level is highest in Delhi and Kolkata with $$70 \%$$ of residents suffering from respiratory disorders and lung cancers due to high SPM levels in populated areas.
Which of the following pollutants is not present in the vehicular exhaust emissions?
Report Question
0%
Lead
0%
Ammonia
0%
Carbon monoxide
0%
Particulate matter
Explanation
Oxides of carbon such as $$CO$$ and $$CO_2$$, oxides of nitrogen, oxides of sulphur, lead, are present along with particulate matter in the vehicular exhaust gases, but ammonia is not formed in these vehicular emissions.
Option B is correct.
Sewage water is purified for recycling by the action of:
Report Question
0%
fish
0%
micro-organisms
0%
fuels
0%
non-biodegradable chemicals
Explanation
Various microbial processes are used to treat this sewage waste by biological methods using microbes feeding on this waste. The bacteria and protozoa consume biodegradable soluble organic contaminants (e.g. sugars, fats, organic short-chain carbon molecules etc.) and bind much of the less soluble fractions into floc. The water is purified and can be recycled and reused again.
There is a possibility of melting of polar ice caps and increase in the level of sea water due to:
Report Question
0%
Depletion of ozone layer
0%
Green house effect
0%
Acid rain
0%
All of the above
Explanation
The greenhouse effect of the earth means the trapping of infrared radiations from the atmosphere and not reflecting it back due to higher levels of carbon dioxide as a major pollutant that traps radiations.
This effect causes the rise in the global temperature resulting in the melting of polar ice caps and rises in sea level.
Option B is correct.
Among the following, which will not help to reduce air pollution?
Report Question
0%
Burn household rubbish in incinerators
0%
Use catalytic converters on motor vehicles
0%
Fix electric precipitators to factory chimneys
0%
Ban smoking in public places such as in offices
Explanation
Some measures indeed help to reduce the stress on the environment like a use of catalytic converters in vehicles and ESPs in chimneys reduce the air pollutants going in an atmosphere. Smoking is injurious to the health of smoker and passive smokers too who have to inhale the smoke in their lungs causing diseases. Incinerators produce a lot of ash and residue which is not suitable for burning so it increases the air pollution.
Cause:
Global warming
Effect:
Ice at the North and South poles may melt causing sea levels to rise and floods to occur.
Which of the following can prevent the effect from happening?
Report Question
0%
Planting trees
0%
Use of unleaded petrol
0%
Use of leaded petrol
0%
Both (A) & (B)
Explanation
Global warming is occurring because of an increase in global temperature. The greenhouse gases are increasing in the air because of the leaded fuel which is used in vehicles giving toxic gases or greenhouse gases and it can be prevented by using unleaded petrol.
This leads to the melting of ice at the North and South poles.
The harmful and unwanted substances which degrade the quality of water are called as ________.
Report Question
0%
water pollutants
0%
soil pollutants
0%
air pollutants
0%
none of the above
Explanation
Any external substance which changes the natural qualities of water is known as a water pollutant. These can be chemical or biological.
These pollutants harm the natural quality of water causing water pollution.
So, the correct option is $$A$$
Modes of controlling pollution in large cities include(s):
Report Question
0%
less use of insecticides.
0%
proper disposal of organic wastes, sewage and industrial effluents.
0%
shifting of factories out of the residential area.
0%
all the above
Explanation
In large cities, environmental health can be maintained by decreased use of insecticides as it affects air quality. All types of household and industrial waste should be handled and disposed of out of the city area and factories inside the residential areas cause great harm to health by polluting the air and water with its wastes, so they must be shifted outside the residential area.
Hence, the correct option is $$\text{D}$$.
The release of carbon dioxide into the air causes:
Report Question
0%
acid rain
0%
eutrophication
0%
global warming
0%
respiratory problems
Explanation
The trapping of solar radiation from the atmosphere and not reflecting it back causes an increase in the temperature of the earth's surface, This phenomenon is called global warming and the gases which trap such radiations are called greenhouse gases. Such as carbon dioxide, methane, etc.
So the release of carbon dioxide into the air causes global warming.
Hence, option $$C$$ (global warming) is correct.
Global warming causes:
1) an increase in the sea level.
2) the melting of ice at mountain peaks.
3) a decrease in food production by plants.
Report Question
0%
I only
0%
I and II only
0%
II and III only
0%
I, II and III
Explanation
The global warming effect causes the rise in the global temperature resulting in the melting of polar ice caps and rises in sea level. This rise in temperature changes the rain cycle and decreases crop production.
The gases released from vehicle exhausts are:
I. carbon monoxide
II. carbon dioxide
III. oxides of nitrogen
Report Question
0%
I and II only
0%
I and III only
0%
II and III only
0%
I, II and III
Explanation
Vehicular exhaust consist of oxides of carbon, mainly carbon dioxide and carbon monoxide, and various oxides of nitrogen resulting from the burning of fuel.
Sewage is a complex mixture containing suspended:
Report Question
0%
organic and inorganic impurities
0%
inorganic impurities
0%
organic impurities
0%
food wastes
Explanation
Sewage contains both organic and inorganic impurities, that include food wastes and microorganisms (organic), detergents (inorganic), etc.
Choose the option which justifies the given statement:-
Air is considered a mixture, not a compound.
Report Question
0%
It is possible to separate air into its constituent gases by physical methods like fractional distillation.
0%
Air does not have a fixed formula like compounds.
0%
Air shows properties same as the constituent gases present in it.
0%
All of the above
Explanation
Air is considered as mixture of many gases because air doesnot have fixed formula like compounds. Also it doesnot show property same as the constituent gases present in it. And it's component can be separated into its constituent gases by physical methods like fractional distillation. So all of the above statement conclude that air is mixture.
What is the composition of air ?
Report Question
0%
70% oxygen, 29 % nitrogen and 1% other
0%
78% nitrogen, 21% oxygen and 1% other gases
0%
77% nitrogen, 21% oxygen and 2% other gases
0%
None of the above
Explanation
$$\bf{Hint:}$$
Air is a homogeneous mixture of different gases with
uniform composition
.
$$\bf{Correct \ answer:}$$
Option $$B$$
$$\bf{Explanation \ for \ correct \ option:}$$
Major components of Air are Nitrogen, Oxygen, Carbon Dioxide, Water Vapor, and Other Gases.
These gases are colorless and odorless and hence, we can’t see them but only feel them.
It consists of $$78$$% nitrogen, $$21$$% oxygen and $$1 $$% other gases including carbon dioxide - $$0.03$$%.
Which of the following gases do not form part of the atmosphere?
Report Question
0%
Nitrogen
0%
Chlorine
0%
Carbon idoxide
0%
Oxygen
0%
Ozone
Explanation
Nitrogen$$(N_2)$$, Carbon dioxide$$(CO_2)$$, Oxygen$$(O_2)$$, Ozone$$(O_3)$$ are part of the atmosphere but chlorine$$(Cl_2)$$ is not a part of atmosphere.
So answer is B.
Air is regarded as a mixture because:
Report Question
0%
its pressure may vary
0%
its temperature may change
0%
its volume changes under different conditions
0%
its composition may vary
Explanation
Air is composed of various gases in different proportions which can be separated using physical methods.
Which is not a green house effect gas?
Report Question
0%
$$CO_2$$
0%
$$H_2$$
0%
CFC
0%
Methane
Explanation
A greenhouse gas is any gaseous compound in the atmosphere that is capable of absorbing infrared radiation, thereby trapping and holding heat in the atmosphere. By increasing the heat in the atmosphere, greenhouse gases are responsible for the greenhouse effect, which ultimately leads to global warming. The most significant greenhouse gases are water vapour (H$$_2$$O), carbon dioxide (CO$$_2$$), methane (CH$$_4$$) and nitrous oxide (N$$_2$$O), according to the Environmental Protection Agency (EPA). Chlorofluorocarbons (CFCs), once used as refrigerants and aerosol propellants until they were phased out by international agreement, are also greenhouse gases. Hence, H$$_2$$ is not a greenhouse gas.
Therefore, the correct answer is option B.
Which of the following gases burns in air?
Report Question
0%
Nitrogen
0%
Carbon dioxide
0%
Carbon monoxide
0%
Helium
Explanation
Out of the given options, nitrogen, carbon dioxide, and helium do not burn in the air. But carbon monoxide burns in the air to produce carbon dioxide.
Purification of water for civil supplies is done by:
Report Question
0%
Chlorination
0%
Distillation
0%
Filtration
0%
Decantation
Explanation
Purification of municipal water supplies is done by the method of chlorination. Water is treated by using chlorine as water disinfectant which kills the pathogenic bacteria or microbes present in the water, making water suitable for drinking purposes.
0:0:1
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
0
Answered
0
Not Answered
0
Not Visited
Correct : 0
Incorrect : 0
Report Question
×
What's an issue?
Question is wrong
Answer is wrong
Other Reason
Want to elaborate a bit more? (optional)
Practice Class 8 Chemistry Quiz Questions and Answers
<
>
Support mcqexams.com by disabling your adblocker.
×
Please disable the adBlock and continue.
Thank you.
Reload page
