10th Class Chemistry Chapter 6 Short Questions with Answers Solved

Question: 1

What are major constituents of troposphere?

Answer: 1

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the major constituents of troposphere are nitrogen and oxygen gases. These gases comprise 99% by volume of earths' atmosphere

Question: 2

What is composition of dry air ?

Answer: 2

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Nitrogen 78.09

Oxygen 20.94

Argon 0.93

Carbon dioxide 0.03

Question: 3

Write is difference between atmosphere and environment?

Answer: 3

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Atmosphere is the envelope of different gases around earth.

Question: 4

What do you mean by an air pollutant?

Answer: 4

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The harmful substances present in air are called air pollutants. Air pollutants change the weather, badly affects the human health, damage the plants and destroy buildings.

Question: 5

Why are the flood risks increasing?

Answer: 5

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Because global warming melts glaciers and snow caps that are increasing flood risks and intense tropical cyclones.

Question: 6

Define atmosphere?

Answer: 6

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Atmosphere is the envelope of different gases around the earth. It extends continuously from earth' surface outwards without any boundary. About 99% of atmospheric mass likes within 30 km and 75% lies within the lowest 11 km.

Question: 7

Define pollutant, also writes its factors on which it depends?

Answer: 7

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A pollutant is a waste material that pollutes air, water and soil. *.Fators. * Chemical nature * Concentration *Persistence.

Question: 8

Where is the ozone layer found?

Answer: 8

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Ozone is present throughout the atmosphere. But its maximum concentration called ozone layer lies in stratosphere region about 25 to 30 km away from the Earth's surface.

Question: 9

How temperature of atmosphere is maintained.

Answer: 9

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Although concentration of carbon dioxide and water vapours is negligible in atmosphere, play a significant role in maintaining temperature of atmosphere. Both of these gases allows visible light to pass through but absorbs infrared radiations emitted by earth's surface. Therefore, these much of outgoing radiations and warm the atmosphere.

Question: 10

What do you mean by Ozone hole?

Answer: 10

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A single chlorine free radical released by teh decomposition of CFCs is capable of destroying upto many lacs of ozone molecules.the region in which ozone layer depletes is called ozone hole.

Question: 11

Where does the ozone layer exist?

Answer: 11

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Ozone layer exists in the middle layer of stratosphere about 25-30 km away from earth's surface

0₂+0 —0₃

Question: 12

What primary pollutants

Answer: 12

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These are waste or exhausi products driven out because of combustion of fossil fuels and organic matter. these are oxides of sulphur oxides, of carbon and oxides of nitrogen .

Question: 13

Why are plants dying day by day? Comment.

Answer: 13

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Acid rain directly damages the leaves of trees and plants, thus limiting their growth. Depending upon the severity of the damage, plants growth can be hampered. Plants capability to resist cold or diseases reduces and ultimately die

Question: 14

Comment burning in open air is preferred.

Answer: 14

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Because in closed area. CO is produced instead of CO2CO causes suffocation and ultimately death.

Question: 15

How detergents make the water unfit for aquatic life ?

Answer: 15

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The detergent remains in water for a long time and makes the water unfit for aquatic life . The phosphates salts present in detergents cause rapid growth of alga in water bodies , which flow over the surface of water . These plants ultimately die and decay . Decaying plants being biodegradable consume oxygen gas present in water . Thus depletion of oxygen gas results in death of aquatic life

Question: 16

What do you mean by air pollutant?

Answer: 16

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The harmful substances present in air are called air pollutants. Air pollutants change the weather, badly, affects the human health, damage the plants and destroy buildings.

Question: 17

Name three primary air pollutants

Answer: 17

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Ans: These are oxides of sulphur (SO2 and SO3 ); oxides of carbon (CO2 and CO); oxides of nitrogen (specially nitric oxide NO); hydrocarbon (CH4 ); ammonia and compounds of fluorine.

Question: 18

How is acid rain produced?

Answer: 18

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When rain water on dissolving air pollutants become more acidic and its pH reduced to 4 thus acid rain is formed on dissolving acidic air pollutants such as sulphur dioxide & nitrogen dioxide by rain water.

Question: 19

Differentiate primary pollutants and secondary pollutants.

Answer: 19

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Secondary Pollutants :These are waste or exhaust product driven out

various reactions of primary pollutants

example : H₂SO₄, H₂CO₃ ,HNO₃ , HF , Ozone ,PAN

Question: 20

List down the names of layers of atmosphere.

Answer: 20

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i. Troposphere ii. Stratosphere iii. Mesosphere iv. Thermosphere

Question: 21

What Secondary pollutants.

Answer: 21

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They are produced by various reactions of primary pollutants.these are sulphuric acid, carbonic acids, hydrofluoric acid ,ozone and peroxyacetyl nitrate.

Question: 22

Why is CO2 called a greenhouse gas?

Answer: 22

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Because CO2 in the atmosphere acts like a glass wall of a green house. It allows visible radiations to pass through it but does not allow the IR radiations to pass through it. It traps some of the infrared radiations emitted by the Earth. Hence. increased concentration of CO2 layer absorbs the infrared radiations emitted by the Earth's surface that prevents heat energy escaping from the atmosphere. It helps to stop surface from cooling down during night. As the concentration of CO2 in air increases, less heat energy is lost from the surface of the earth . Therefore the average temperature of the surface gradually increases . This is called greenhouse effect

Question: 23

What is Existence of ozone layer.

Answer: 23

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It lies in stratosphere region about 25 to 30 km away from earth's surface.

Question: 24

What are the reasons of waterborne diseases?

Answer: 24

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Diseases that spread because of drinking polluted water or eating food prepared with polluted water are called waterborne infectious disease . Water pollution may be due to toxins or microorganisms . Toxins are arsenic , mercury , arsenic , lead and many organic chemicals . Microorganisms are viruses , bacteria , protozoa and worms

Question: 25

What is ozone layer.

Answer: 25

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The maximum concentration of ozone is called ozone layer.

Question: 26

Why sea water is unfit for drinking and agricultural purposes ?

Answer: 26

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Sea water is unfit for drinking and agricultural purposes due to high percentage of dissolved salts . Only 0.2 % of total water on the earth os portable i-e feet for drinking purpose

Question: 27

Define pollutant, also writes its factors on which it depends?

Answer: 27

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A pollutant is a waste material that pollutes air, water and soil.

• Factors

• Chemical nature

• Concentration

• Persistence

Question: 28

Justify, ozone is beneficial for human kind.

Answer: 28

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Ozone is an allotropic form of oxygen consisting of three oxygen atoms. It is formed in bops atmosphere by the association of an oxygen atom with an oxygen molecule in the mid of stratosphere. It absorb cancer causing radiation UV radiation.

Question: 29

What is effect of acid rain on buildings?

Answer: 29

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Acid rain attack the calcium carbonate present in marble and limestone of building" monuments. Thus. these building are getting dull and eroded day by day.

Question: 30

Why the temperature of upper stratosphere is high?

Answer: 30

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In stratosphere's upper region the temperature rises gradually upto 2°C. The presence of 07-Otle (due to absorption of radiations) in this region in responsible for rise of temperature

Question: 31

How waterborne disease can be prevented ?

Answer: 31

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Waterborne diseases can be prevented by taking the following measures

1: Provision of safe water : Drinking water must be properly treated and purified

2: Disposal of sewage : There must be adequate sanitary disposal of sewage . Any type of waste must not be thrown or discharge directly in water supplies or reservoirs

3: Control of toxic chemicals : Chemical contamination can cause acute illness , but often toxic contaminants are slow poisons and carcinogens . There must be a strict control over the use of pesticides and other chemical

Question: 32

Which air pollutant is produced on anaerobic decomposition of organic matter ?

Answer: 32

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Naturally occurring sulphur consisting compounds are emitted in the bacterial decay of organic matter in volcanic gases and forest fires

Question: 33

What do you mean by ozone hole?

Answer: 33

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A single chlorine free radical released by the decomposition of CFCs is capable of destroying upto many lacs of ozone molecules. The region in which ozone layer depletes is called ozone hole

Question: 34

What are major constituents of troposphere?

Answer: 34

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The major constituents of troposphere are nitrogen and oxygen gases. These gases comprise 99% by volume of earth's atmosphere.

Question: 35

List down the names of layers of atmosphere .

Answer: 35

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1: Troposphere

2: Stratosphere

3: Mesosphere

4: Thermosphere

Question: 36

Why the water molecule is polar ?

Answer: 36

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Water molecule has polar structure i-e one end of the molecule is partially while the other end is partially negative because of electronegativity difference between oxygen and hydrogen atoms

Question: 37

Define metallurgy .

Answer: 37

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The process of extraction of a metal in pure form on a large scale with minimum case from its ore by physical or chemical mean is called metallurgy

Question: 38

Write two effects of SO_2.

Answer: 38

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It is colourless gas having irritating smell. It causes suffocation, irritation and severe problems to asthmatic people.

Question: 39

Why are the flood risks increasing ?

Answer: 39

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Because global warming melts glaciers and snow caps that are increasing flood risks and intestine tropical cyclones

Question: 40

Why water is universal solvent give with two unique properties as a reason

Answer: 40

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Water is a universal solvent because it can dissolve almost al the minerals . Its ability to dissolve substances is because of two properties of water

1: Polarity of water molecule

2: Exceptional hydrogen bonding ability

Question: 41

Why the 75% of the atmospheric mass lies within the troposphere ?

Answer: 41

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The major constituent of troposphere are nitrogen and oxygen gases . These two gases volume by volume of Earth's atmosphere Hence it contain 75% of atmosphere mass

Question: 42

Identify as primary or secondary air pollutant. SO₂, CH⁴, HNO₃,NH₃,H₂SO₄,0₃

Answer: 42

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SO_2, CH₄ NH₃ are primary air pollutant. & HNO₃ ,H₂SO₄,0₃ are secondary air pollutant.

Question: 43

Define green house effect.

Answer: 43

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CO₂ forms a layer around earth that absorbs the infrared radiations emitted by earth surf heating up atmosphere, called green house effect.

Question: 44

State the major sources of CO and CO2 emission

Answer: 44

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Sources of oxides of carbon are as follows:

• Both of these gases are emitted due to volcanic eruption and decomposition of organic matter naturally.

• However, the major source for the emission of these gases is combustion of fossil fuels (coal petroleum and natural gas). Fossil fuels burnt in combustion engine of any any industry or open air fires emit CO2 and CO.

Forest fires and burning of wood also emit CO2 and CO. Especially, when supply of oxygen is limited_ emission of CO dominates

Question: 45

What are the names of types of the hard water ?

Answer: 45

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There are two types of water hardness

1: Temporary hardness

2: Permanent hardness

Question: 46

What is difference between atmosphere and environment?

Answer: 46

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Atmosphere :

is the envelope of different gases around earth.

Question: 47

How pesticides cause water pollution ?

Answer: 47

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Fertilizers are used to make up the deficiency of nitrogen , phosphorous etc of the soil because of intensive cultivation of the crops in the recent years

Question: 48

How are sulphur containing compounds emitted naturally?

Answer: 48

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Naturally occurring sulphur containing compounds are emitted in the bacterial decay of organic matter. in volcanic gases and forest fires

Question: 49

Define atmosphere .

Answer: 49

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Atmosphere is the envelope of different gases around the earth . It extends continuously from earth's surface outwards without any boundary . About 99% of atmospheric mass likes within 30 km And 75% lies within the lowest 11km

Question: 50

What threats are to human health due to SO₂ gas as air pollutant ?

Answer: 50

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SO2 is a colorless gas having irritating smell , It causes suffocation , irritation and severe respiratory problems to asthmatic people

Question: 51

Where is the ozone layer found?

Answer: 51

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Ozone is present throughout the atmosphere. But its maximum concentration called ozone layer lies in stratosphere region about 25 to 30 km away from the Earth's surface

Question: 52

CO₂ is responsible for heating up atmosphere, how?

Answer: 52

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Because CO2 in the atmosphere acts like a glass wall of a green house. It allows UV radiations to pass through it but does not allow the IR radiations to pass through it. It traps some of the infrared radiations emitted by the Earth. Hence, increased concentration of CO2 layer absorbs the infrared radiations emitted by the Earth's surface that prevents heat energy escaping from the atmosphere. It helps to stop surface from cooling down during night. As the concentration of CO2 in air increases, less heat energy is lost from the surface of the Earth. Therefore, the average temperature of the surface gradually increases. This is called greenhouse effect

Question: 53

Explain why non ionic polar compounds are soluble in water ?

Answer: 53

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Water molecule is composed of of hydrogen and oxygen atom. Because of two O-H bonds and two lone pairs , one H₂O molecule can form hydrogen bonding with four other H₂O molecules . This unique behaviour of water enables it to dissolve many polar non-ionic compounds having hydroxyl group (-OH) like alcohols , organic acids , glucose , sugar etc by forming hydrogen bonds with them

Question: 54

Why is ozone depleting in atmosphere?

Answer: 54

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chlorofluorocarbons (CFCs ) (used as refrigerants in air conditioners and refrigerators) are major cause of depletion of ozone layer. These compounds leak in one way or other escape and diffuse to stratosphere. Ultraviolet radiations break the C-Cl bond in CFCI₃ and generates chlorine free radicals

Question: 55

How is aquatic life affected by acid rain?

Answer: 55

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Aquatic life present in lakes also suffers because of high concentration of these metals. Especially high concentration of aluminium ions clogs the fish gills. It causes suffocation and ultimately death of fish.

Question: 56

How combustion of fossil fuels in internal combustion engine produces oxides of nitrogen?

Answer: 56

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Combustion of fossil fuels in internal combustion engines, in thermal power stations and factories where huge amount of coal is burnt, NO is formed by the direct combination of nitrogen and oxygen as shown

N₂(g) + O₂→2NO(g)

However, it quickly reacts with air to form nitrogen dioxide. NO2 is highly toxic gas.

2NO(g) + O₂(g)→ 2NO₂(g)

Question: 57

What is water pollution ?

Answer: 57

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Water pollution is contamination of water bodies e.g lakes , rivers , oceans and ground water . Water pollution occurs when pollutants are discharged directly or in directly into water bodies without adequate treatment to remove harmful compounds

Question: 58

How flood risks are increasing?

Answer: 58

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Global warming melts glaciers and snow caps that are increasing flood risks and intense tropical cyclones.

Question: 59

Define water softening and name the method of removing hardness ?

Answer: 59

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The removal of Mg²⁺ and Ca²⁺ions which are responsible for the hardness is called water softening Methods

Question: 60

CO is an hidden enemy, explain its action.

Answer: 60

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CO is an air pollutant. It is a health hazard being highly poisonous gas. Being colorless and odorless, its presence cannot be noticed easily and readily. When inhaled. it binds with the haemoglobin most strongly than that of oxygen . Thus hindering the supply of oxygen in body . Exposure to higher concentration of CO causes headache and fatigue . If inhaled for a long time it results in breathing difficulties and ultimately death . It is the reason burning is not allowed in closed places . It is advised to switch off coal or gas heaters ,cooking range etc before going to sleep

Question: 61

Explain the chemistry of removing the temporary hardness by boiling water .

Answer: 61

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Temporary harness of water is easily removed by boiling water . On boiling , calcium bicarbonate Ca(HCO)₃decomposes to produce insoluble calcium carbonate , which precipitates of the solution

Question: 62

What disease or hazards are for human beings b acute cadmium , lead and mercury poisoning can causes?

Answer: 62

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Acute cadmiumpoisoning causes . High blood pressure , kidney damage and destructing of red blood cells

1: Acute lead poisoning causes dysfunction of kidney , liver , brain , nervous system and reproductive system

2: Mercury poisoning causes , Neurological damage

Question: 63

Explain the phenomenon of decreasing temperature in troposphere

Answer: 63

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Although, concentration of carbon dioxide and water vapours is negligible in atmosphere, yet they play a significant role in maintaining temperature of the atmosphere. Both of these gases allow visible light to pass through but absorb infrared radiations emitted by the Earth's surface. Therefore, these gases absorb much of the outgoing radiations and warm the atmosphere. As the concentration of gases decreases gradually with the increase of altitude. correspondingly temperature also decreases at a rate of 6C per kilometer.

Question: 64

Tell some use of water in our life .

Answer: 64

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Uses of water in our daily life are for drinking ,cooking , washing , purposes etc

Question: 65

If you add a lamp of cesium to water in a glass tough , what will happen ?

Answer: 65

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The reaction is so vigorous that the tough will shelter into small pieces

Question: 66

Define water born diseases

Answer: 66

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Diseases that spread because of drinking pollutes water or eating food prepared with polluted water are called waterborne infectious disease

Question: 67

What do you mean by boiler scales ? How are they removed ?

Answer: 67

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Hard water is unfit for use in stem engines ,boilers and turbines because insoluble calcium and magnesium salts deposit inside . They are called scales They are bad conductors of heat and hence more fuel is used . Insoluble calcium and magnesium sulphates not only reduce the efficiency of the engine but also cause the boiler to burst . They can be removed by using HCL

Question: 68

How acid rain effects aquatic life?

Answer: 68

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(i) Acid rain on soil and rocks leaches heavy metals (Al. Fig, Pb, Cr. etc) with it and discharges these metals into rivers and lakes. This water is used by human beings for drinking purpose. These metals accumulate in human body to a toxic level. On the other hand, aquatic life present in lakes also suffers because of high concentration of these metals. Especially high concentration of aluminium ions clogs the fish gills. It causes suffocation and ultimately death of fish.

(ii) Acid rain attacks the calcium carbonate present in the marble and limestone of buildings and monuments. Thus, these buildings are getting dull and eroded day by day.

(iii) Acid rain increases the acidity of the soil. Many crops and plants cannot grow properly in such soil. It also increases the toxic metals in the soil that poisons the vegetation. Even old trees are being affected due to acidity of soil. Their growth is retarded. They get dry and die.

(iv)Acid rain directly damages the leaves of trees and plants, thus limiting their growth. Depending upon the severity of the damage. plants growth can be hampered. Plants capability to resist cold or diseases reduces and ultimately die

Question: 69

What is the principle of removing permanent hardness of water ?

Answer: 69

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Permanent hardness can only be removed by using chemicals . Calcium (Ca²⁺) and magnesium (Mg²⁺) are removed as insoluble salts by adding washing soda (Na₂Co₃) or sodium zeolite

Question: 70

Give three effects of water pollution .

Answer: 70

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1: It is damaging aquatic life , thus breaking a link of food chain

2: It reduces the aesthetic quality of lakes and rivers

3:It is unfit for cleaning or washing purposes

Question: 71

What is an industrial waste ?

Answer: 71

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Industrials units are installed to produce the desired substances (chemicals , cloth , leather goods , paper, plastic , items , petrochemicals and rubber items) on commercial scale to meet the needs of the society . But unfortunately al the industrial units discharge their wastes (chemicals and solid materials) either to open the ground or to water channels . This is called industrial effluent . The industrial effluent may be highly toxic organic chemicals , inorganic salts , heavy metals , minerals acids , oil and greases etc

Question: 72

.Why acid rain damages buildings?

Answer: 72

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Acid rain attacks the calcium carbonate present in the marble and limestone of buildings and monuments. Thus, these buildings are getting dull and eroded day by day.

Question: 73

Which bacteria causes the cholera ?

Answer: 73

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Cholera is an acute infection caused by the bacteria 'Vibrous cholera which may be found in water contaminated by human feces . Cholera causes severe diarrhea and can be fatal

Question: 74

What is capillary action ?

Answer: 74

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Capillary action is a process by which rises up from the roots of plants to leave . This process is vital for the survival of the land plant

Question: 75

How water rises in plants ?

Answer: 75

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It has high surface tension . This unique property of water is responsible for its high capillary action . Capillary action is the process by which water rises up from the roots of plants to leaves . This process is vital for the survival of the land plants

Question: 76

Which salts are responsible for hardness of water ?

Answer: 76

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The rain water while coming down absorbs carbon dioxide from the atmosphere . The water mixed with carbon dioxide , when passes through the beds of the soil converts insoluble carbonates of calcium and magnesium into soluble bicarbonates . It may also dissolve chlorides and suphates of calcium and magnesium . These salts make the water hard

Question: 77

What do you mean by fluorosis ?

Answer: 77

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Fluorosis is a diseases caused by the consumption of excess fluoride can cause bones and teeth damage

Question: 78

Discuss about hookworm ?

Answer: 78

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Hookworm is a parasitic warm that affects the small intestine . Sever cases can result in anemia and stunted growth in children . Hookworm larvae enter the body through skin , often via the feet and spread by poor sanitary conditions . Hookworms infect about one billion people worldwide per anum

Question: 79

Tell about sodium zeolite .

Answer: 79

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Sodium zeolite (an ion exchanger) . It is a naturally occurring resin of sodium aluminium silicate NaAl (SiO₃)₂which can also be prepared artificially . It is used for softening of water at domestic as well as on industrial scale

Question: 80

How water used as a cleansing agent in industries causes pollution .

Answer: 80

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Water used as cleaning agent in industries is directly discharged out . This water contains all kinds of toxic chemicals and detergents

Question: 81

What is function of fertilizers ?

Answer: 81

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Fertilizers are used to make up the deficiency of nitrogen , phosphorous etc of the soil because of irrigation run-off from agricultural field

Question: 82

Which forces are responsible for dissolving polar substances in water ?

Answer: 82

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Water is the universal solvent because it can dissolve almost all the minerals . Its ability to dissolve substances is because of two unique properties of water

1: Polarity of water molecule

2: Exceptional hydrogen bonding ability

Question: 83

What is dysentery ?

Answer: 83

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Dysentery is an intestinal disease which is typically caused by certain bacteria or parasites . It is characterized by severe diarrhea that may be accompanied by blood or mucous

Question: 84

Tell two reasons and importance of water .

Answer: 84

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Firstly , it is essential and major components of each and every living cell

Secondly , it provides an environment for animals and plants that live in water

Question: 85

Why use of detergents is increasing day by day ?

Answer: 85

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Water used as cleaning agent in industries is directly discharged out . This water contains all kinds of toxic chemicals and detergents

Question: 86

Why non-polar compounds are insoluble in water ?

Answer: 86

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Many covalent substances like benzene , ether , octane etc , which do not have polar ends or bonds are not attached by water molecules . Therefore non-polar compounds do not dissolve in water

Question: 87

How water dissolve sugar and alcohol?

Answer: 87

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Water molecule is composed of oxygen and hydrogen atoms . Because of two O-H bonds and two lone pairs , one H₂O molecule can form hydrogen bonding with four H₂O molecules , which are arranged tetraedrally around the H₂O molecule . This unique behaviour of water enables it to dissolve many polar non-ionic compounds having hydroxyl group (-OH), like alcohols , organic acids , glucose , sugar , etc by forming hydrogen bonds with them

Question: 88

How sodium zeolite softens water ?

Answer: 88

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Sodium zeolite is a naturally occurring resin of sodium aluminium silicate NaAl(SiO₃)₂, which can also be prepared artificially . It is used for softening of water at domestic as well as on industrial scale . When water is passed through resin , sodium ions of the resin are exchanged with the unwanted calcium and magnesium ions of the hard water

Question: 89

Name preventive methods of waterborne disease

Answer: 89

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1: Provision of safe water

2: Disposal of sewage

3: Control of toxic chemicals

Question: 90

How decaying plants consume oxygen ?

Answer: 90

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When algae dies , bacteria consume oxygen of the water for decomposition of algae . As a result oxygen depletes in this water . Aquatic animals feel suffocation and ultimately die due to insufficient supply of oxygen

Question: 91

What is hepatitis ?

Answer: 91

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It is liver inflammation commonly caused by one of five viruses called hepatitis A,B,C,D and E . Hepatitis A and E can be transmitted by contaminated water

Question: 92

How limestone dissolves in water ?

Answer: 92

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Gypsum is sparingly soluble in water , while limestone is insoluble in water . However in the presence of carbon dioxide small quantity of limestone is soluble in water according to the chemical reaction

Chemistry Chapters

10th Class Chapter 6 Chemistry Short Questions

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