NIOS Class 10 Science & Technology Chapter 26 Solution

NIOS Class 10 Science & Technology Chapter 26 Solution – Air And Water

NIOS Class 10 Science & Technology Solution Chapter 26 Air And Water. NIOS Class 10 Science & Technology Chapter 26 Question Answers Download PDF. NIOS Class 10 Science Notes.

NIOS Class 10 Science & Technology Chapter 26 Solution

Board NIOS
Class 10th (Secondary)
Subject                                                Science and Technology (262)
Topic Question Answer, Solution, Notes







1)A chemical substance may occur as an element, mixture or compound. Towhich category does air belong?

Ans: – The air belongs to the category in mixture.


2) Name the major constituents of air. Which constituents are inevitable for survival of plants and animals?

Ans: –The major constituents of air is nitrogen gas.

The constituents which are inevitable for the survival of plants and animal is oxygen.


3)If you were to compare the relative amounts of nitrogen and oxygen in the atmosphere. Which will be four times the other?

Ans: – As in air the amount of nitrogen is approximately to 80% and oxygen is about 20%. So, nitrogen is four times with the oxygen.


4)Air also contains water vapour. But is its percentage in air the same at all places?

Ans: – No the percentage of air is nit same in all places they are variable.




1)Why is oxygen essential for life? What would happen if there is no oxygen in air?

Ans: – Oxygen is essential for the respiration of animal. So, without this there is no possibility to live. For this reason, oxygen is essential.


2)Carbon dioxide acts as food for plants. Name the process in which it isutilized for making food.

Ans: – The process which carbon dioxide acts as food is the photosynthesis process.


3)What is dry ice and what is it used for?

Ans: – The dry ice is nothing but the solid carbon dioxide.


4)If you were to analyse all proteins, you would find a particular element common to all. Which one is it?

Ans: – The nitrogen is common in all the particular element of protein.





1)What happens to atmospheric pressure as we climb a mountain?

Ans: –  The air pressure will be less in mountain while climbing as compared to the plain.


2)At high altitude the people find their nose bleeding. Why?

Ans: –  As blood pressure in blood vessels of the body is morethan the air at high altitude, because of these capillaries burst and bleedingoccurs.


3)Which layer of atmosphere is the closest to the earth’s surface and which isthe farthest from earth’s surface?

Ans: – The Troposphere is closed to earth’s surface and Thermosphere is farthest from the earth’s surface.


4)In which layer of atmosphere is ozone layer present?

Ans: –The ozone layer is present in stratosphere.


5)Name (i) a greenhouse gas (ii) gas responsible for acid rain (ii) chemicalscausing ozone hole.

Ans: – Thegreenhouse gas is methane.

The gas responsible for the acid rain is sulphur dioxide.

The chemical causing of ozone layer because of the CFC.




1)It is said that more of earth is water than land. How much of the earth’s surface is covered by water?

Ans: – The one third of the earth is covered with the land and the remaining two third is water.


2)Name any two sources of water.

Ans: – The two source of water is rain and ice bar in pole.


3)Is rainwater pure or impure? Give one reason to support your answer.

Ans: – Normally the rain water is pure or distilled the polluted air present in the atmosphere makes it too acidic.


4)What does chlorination do to water in order to purify it?

Ans: –The chlorination of water is made for the disinfection of the water as the chlorine is works as a disinfectant by mixing in water.


5)I could not form lather with soap while washing my hands, which type ofwater was it?

Ans: –As there is no lather of this soap so the water must be hard water.


6)Name the type of hardness caused to water due to presence of bicarbonatesof Ca2+ or Mg2+.

Ans: – The presence of bicarbonate of Ca (+2) and Mg (2+) in water caused the temporary hardness of water.


7)Name the type of hardness caused to due to presence-of chloride or sulphateof Ca2+ or Mg2+.

Ans: – The presence of chloride or sulphide of Ca (2+) and Mg (2+) in water makes it as permanent hardness.


8)Which type of hardness is removed by the following:

(i) boiling _____temporary________

(ii) ion exchange method. ___permanent___________


9)Is water a polar or a non-polar solvent? Why do you think so?

Ans: – The water is polar solvent.


10)At what temperature does water take up least space?

Ans: – In the temperature of 4℃ the water takes up least space.



1) State any two uses of harvesting rain water?

Ans: – The uses of harvesting rain water is –

  • Flooding control.
  • Groundwater saves.


2) How would industries and agriculture suffer in the event of acute scarcity of water?

Ans: –In industries the water scarcity because of coolant purpose, production of steam, use as solvent for chemical reaction.

In Agriculture the water scarcity because of irrigation of crops, germination of seeds as reason of that the growth of plantswould be affected.\


3)What does rainwater do to ground water?

Ans: – The rain water increase the ground water level.


4)Why does rain water prove to be suitable for washing with soap?

Ans: – As the rain water is pure or soft water this is suitable for the Washing with the soap.



1.) Multiple choice type questions.

i.) Air is

a) compound

b) element

c) mixture

d) none of these.

Ans: – Option(c).


ii.) Major components of air are

a) CO2 and H2O

b) N2 and O2

c) CO2 and He

d) H2O and Xe.

Ans: – Option(b).


iii.) The instrument used to measure humidity is

a) barometer

b) hygrometer

c) lactometer

d) thermometer.

Ans: – Option(b).

iv.) Water has maximum density at

a) 0°C

b) 10 °C

c) 5°C

d) 4 °C.

Ans: – Option(d).


2)List the utility of oxygen and nitrogen in our lives.

Ans: – The oxygen is very necessary for the respiratory activity in our body for the production of energy. The nitrogen makes a balance between the human and animal, plant which we know as a nitrogen cycle.


3)What is atmospheric pressure?

Ans: – The pressure of the air in a particular area is known as atmospheric pressure. This pressure is more in plain as compared to mountain.


4)How does the atmospheric pressure depend on altitude?

Ans: –The atmospheric pressure decreases when we go to the mountains from the plain.


5)Give an activity, which proves that air exerts pressure.

Ans: – In the mountains bleeding is seen in our nose as the air pressure is less as compared to the plain. So, by this example we can see the effect of air pressure.


6)What is relative humidity?

Ans: – The relative humidity is the ratio of the moisture present in the air as compared to the moisture present in normal days.


7)What is the different source of water? Mention any two.

Ans: – The source of water is rain, or ice bar in polar area.


8) Why is water called as universal solvent?

Ans: – As almost everything can be dissolved in water so for this reason, we can say that water is universal solvent.


9)What are the different ways to purify drinking water? What is the role of chlorination?

Ans: –The way of purification of drinking water is by boiling it as when boiled the bacteria present in water destroyed.

The chlorine is used as disinfectant while it mixing in water or by the presence of it in bleaching powered. So, it is a disinfectant substance.


10)What do you mean by hard and soft water? Explain the types of hardness in water.

Ans: – The hard water is when the chloride of the ions of calcium or magnesium present in any water then we can say that the water is hard water.


11)How are the temporary and permanent hardness removed from water?

Ans: – The temporary hardness is removed by the bicarbonate of calcium or magnesium ion and the permanent hardness is removed by the mixing of sulphide of this ion.


12) Explain the following properties of water.

Ans: – The water is used as universal solvent which tells us everything can be dissolve in water by any way.


13)(i) Surface tension(ii) Density.

Ans: –  The pressure of water in a particular area is known as the surface tension.

The ratio of the mass to the volume is known as the density of that substance.


14)What is rainwater harvesting? How is it beneficial for everyday life?

Ans: – The rainwater harvesting is the best way to save the water for the uses of different purpose like the in vegetation or household works.

By harvesting the rain water the level of ground water increased.


15)Why is the presence of carbon dioxide in atmosphere essential? Give two reasons.

Ans: –The presence of carbon dioxide in atmosphere is helpful in the photosynthesis process which helps the oxygen production from the plant and food of the plants.


16)Give any two medical uses of oxygen.

Ans: – The oxygen is used in different area like the oxygen cylinder is used in when the oxygen taking efficiency of a person is affected.


17)What are primary and secondary air pollutants? Give one example of each.

Ans: – Primary pollutants are CO2, NO2, SO2 etc.

The secondary pollutants are the combine particles of hydrocarbon and the sulphur oxide.


18)What are the sources of the following pollutants: (i) Chlorofluorocarbons (ii)Nitrogen oxides (iii) Particulate matter.

Ans: –Chlorofluorocarbons: – The emission from refrigerator.

Nitrogen oxides: – From combustion reaction.

Particulate matter: – From ashes, smog.


19)Why are the following substances considered air pollutants: (i) Carbon monoxide (ii) Carbon dioxide (iii) Sulphur oxides (iv) Volatile organic compounds.

Ans: – As this substance when present in air makes the air polluted and when we take sit then we see that the different activity of the body is hampered by taking this toxic air.


20)What are (i) photochemical smog and (ii) ground level ozone.

Ans: – Photochemical smog: – The high levels of nitrogen and ozone when mixed in air create a ozone hole in the atmosphere region which is known as photochemical smog.

Ground level ozone: – In automobile industry’s these types of   violating hydrocarbon compound are present.


21)What are (i) point source pollution and (ii) non-point source pollution? Giveone example of each.

Ans: – Point source pollution: – The pollution source when is known then this pollution is known as pint source pollution. Like polluted water came from factories.

Non point pollution: – When the polluted elements source not known to us like after thunderstorm different types of polluted substance are seen in wide area in locality.


22) Dive any two of water for each of the following purposes (i) domestic (ii)industrial and (iii) agricultural.

Ans: –  Domestic: – For cooking, drinking.

Industrial: – For cooling plant, smelting.

Agriculture: – For the irrigation purpose.


23)What do you mean by conservation of water? How is it useful?

Ans: – The conservation of water means the storing of water for the difference purpose uses like the uses in agricultural, household works etc.


24)You are in charge of the resident’s welfare association. /Prepare two slogans to make residents aware of need for conservation of water.

Ans: – The slogan which will create a awareness in the resident is SAVE THE WATER FOR OUR FUTURE GENERATIONS. As these types of awareness is also very necessary for our water harvesting.


25)The atmospheric envelop around living beings is the provider of the gases essential for their survival which are these gases, what is their proportion inair and how are they responsible for survival?

Ans: – This gas is carbon dioxide as this gas play an important role in the photosynthesis process. As this gas helps the plant for the making of their food. In this process the oxygen gas also come out.


26)How does rain water pollute water bodies with the air pollutants.

Ans: – As the rain water become acidic with the presence of Different toxic gases present in air. So, when this water is falling on the water resources then we see that water is polluted.


27) Recall five properties of water and write a paragraph justifying that water isan indispensable resource.

Ans: – The indispensable resources are very necessary for our future generations. As day by day the uses of the water is increasing but we should do it in a specify manner like only for the essential uses. So, the water harvesting is very necessary.


28)How does boiling of hard water convert it such that it can be used for washingclothes?

Ans: –As in hard water there present a substance like the calcium or magnesium in its sulphide forms so, by boiling it we can do that. As the water is also known as the universal solvent.

Updated: March 3, 2022 — 4:49 pm

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