Importance Of Water And Its Resources Class-6th Goyal Brothers Chemistry Solutions Chapter-4 Unit-1

Importance Of Water And Its Resources ICSE Class-6th Goyal Brothers Chemistry Solutions Chapter-4 Unit-1. We Provide Step by Step Answers of Objective, True False , Fill in the blanks, Match the following , Short/Long Answer Type of Chapter-4 Unit-1, Importance Of Water And Its Resources Visit official Website  CISCE  for detail information about ICSE Board Class-6th.

Importance Of Water And Its Resources ICSE Class-6th Goyal Brothers Chemistry Solutions Chapter-4 Unit-1

Board ICSE
Class 6th
Subject Chemistry
Book Name Goyal Brothers
Chapter-4 Water
Unit-1 Importance Of Water And Its Resources
Topic Solution of exercise questions
Session 2023-24

Importance Of Water And Its Resources ICSE Class-6th

Goyal Brothers Chemistry Solutions Chapter-4 Unit-1

OBJECTIVE TYPE QUESTIONS

Question : A. Fill in the blank spaces by choosing the correct words from the given list :

List : clay, water vapors, common salt, hydroelectric, leaves

  1. Water is essential for running hydroelectric power plants.
  2. River water contains clay and fine particles of sand.
  3. Seawater contains 24 g of common salt in every liter.
  4. Cloud or mist is an example of condensed water vapour.
  5. The plants release water through their leaves.

Question : B. Statements given below are incorrect. Write the correct statements :

1. Distilled water is fit for human consumption.

Answer: Distilled water is unfit for human consumption.

2. Well water is not potable water.

Answer: Well water is not potable water.

3. Potable water is obtained from sea water by the process of evaporation.

Answer: Potable water is obtained from ground water by the process of evaporation.

4. Clear river water is treated with carbon dioxide gas to kill germs and bacteria.

Answer: Clear river water is treated with chlorin gas to kill germs and bacteria.

5. Potable water must not contain any dissolved gases.

Answer: Potable water must contain any dissolved gases.

Question : C. Match the statements in Column A, with those in Column B.

Column A

Column B

1. Name of potable water generally consumed in India villages.

1. Rainwater

2. Purest form of natural water.

2. Seawater

3. Impurest form of natural water.

3. Sedimentation

4. A gas commonly used to kill germs and bacteria in city water supply.

4. Well water

5. The process by which suspended impurities in the river water settle down.

5. Chlorine

Answer:

Column A

Column B

1. Name of potable water generally consumed in India villages.

1. Well water

2. Purest form of natural water.

2. Rainwater

3. Impurest form of natural water.

3. Seawater

4. A sub-multiple unit of area used for measuring the area of a postal stamp.

4. Chlorine

5. The process by which suspended impurities in the river water settle down.

5. Sedimentation

 

Question : D. Write ‘True’ or ‘False’ for the following statements:

Statement  True/False

1. Pure water is a colourless liquid having a fine taste.

2. All living beings do not contain more than 20% of water.

3. Dissolved gas in natural water are necessary for the respiration of water plants and water animals.

4. River water is most impure form of water.

5. Chlorine gas is added to clear water, to kill germs and bacteria.

Answer:

Statement  True/False

1. Pure water is a colourless liquid having a fine taste.

F

2. All living beings do not contain more than 20% of water.

F

3. Dissolved gas in natural water are necessary for the respiration of water plants and water animals.

T

4. River water is most impure form of water.

F

5. Chlorine gas is added to clear water, to kill germs and bacteria.

T

Question : E. Tick (√) the most appropriate answer :

1. River water is a :

(a) suspension

(b) solution

(c) compound

(d) element

Answer: option (c) compound is correct

2. Potable water is :

(a) Transparent only

(b) Transparent and colorless only

(c) Transparent, colorless and has taste

(d) Transparent, colorless, has taste and free from germs and bacteria

Answer: option (b) Transparent and colorless only is correct

3. Purest form of natural water is :

(a) Spring water

(b) Rainwater

(c) Well water

(b) Seawater

Answer: option (b) Rainwater is correct

4. Water used for chemical reactions in a laboratory is purified by :

(a) filtration

(b) evaporation

(c) distillation

(d) sedimentation

Answer: option (c) distillation is correct

5. Potable water is obtained from river water by the the process of :

(a) Sedimentation only

(b) Sedimentation and filtration only

(c) Sedimentation and chlorination only

(d) Sedimentation, filtration and chlorination only

Answer: option (d) Sedimentation, filtration and chlorination only is correct

Importance Of Water And Its Resources ICSE Class-6th

Goyal Brothers Chemistry Solutions Chapter-4 Unit-1

STUDY QUESTIONS

Que: 1. State five important uses of water.

Answer 1: five important uses of water:

  • Water is used for daily purpose like cooking , bathing , cleaning and drinking.
  • Water used as a universal solvent.
  • water maintains the temperature of our body.
  • Water helps in digestion in our body.
  • water is used in factories and industries.
  • Water is used to grow plants , vegetables and crops.

Que: 2. Rainwater is considered the purest form of natural water. Explain the statement.

Answer 2: Rain water is considered to be the purest form of natural water as it is directly comes from the condensation of water droplets. In the presence of sun, the water evaporates from the seas, oceans , rivers (from all the natural open resources of water) leaving behind all the impurities and form the cloud. From there it is directly come to the earth in the form of rain. But now a days environment is not clean and air is highly polluted with toxic gases which combines with the rain water making it acidic (known as acid rain).Hence rain water is no more the purest form of natural water.

Que: 3. Name the gases which dissolve in rainwater before it reaches the ground. What harm can be caused by these gases ?

Answer 3: Gases that dissolve in rainwater before it reaches the ground:-

  1. Oxygen
  2. Nitrogen
  3. Carbon dioxide

In areas having industries and regions which have recently observed volcanic eruptions the rainwater dissolves following gases from the atmosphere

  1. Sulfur dioxide
  2. Nitrogen dioxide

The harms caused by these gases:-

  1. Carbon dioxide when dissolved in water forms Carbonic acid, this Carbonic acid reacts with Limestone and Marble and turns it yellowish in color and damages it.
  2. Sulfur dioxide when dissolved in water forms Sulphuric acid which is a very corrosive and dangerous acid.
  3. Nitrogen dioxide when dissolved in water forms Nitric acid that damages the proteins in the skin.
  4. Sulfuric and Nitric acid together forms the acid rain and damage crops, and buildings, and if any human or animal comes in contact with it, they can suffer severe injuries.

Que: 4. Name (a) three dissolved impurities and (b) three suspended impurities present in the river water.

Answer: (a) Three dissolved impurities in river water are

  1. Salts of calcium and sodium dissolve from the soil into the water.
  2. Gases like Sulphur dioxide and nitrogen dioxide get dissolved in water from the air.
  3. Chemicals and domestic waste from cities and industries.

(b) Three suspended impurities in river water are :

  1. Particles of soil like clay and fine sand particles get washed away with rainwater.
  2. Remains of plants and animals living near the river. For example – wood, dead leaves, bird feathers etc.
  3. Living organisms like germs and bacteria come down from domestic and hospital waste.

Que: 5. Name the major salts dissolved in sea water. What is the maximum percentage of the salt which is found in seawater ?

Answer: Seawater – It is a form of natural surface water that contains the highest amount of impurities.

Major salts dissolved in seawater are of

  1. Sodium
  2. Calcium
  3. Magnesium

Seawater also contains trace amounts of salts of other metals as well.

  • The average content of salts in seawater is 26 g per litre. the majority of which is common salt that constitutes around 24 g per litre.
  • The maximum concentration of dissolved salts in seawater can go up to 35 g per litre, after that the concentration does not increase.

Que: 6. Write a short note on water cycle.

Answer 6: The water cycle shows the continuous movement of water within the Earth and atmosphere.

Que: 7. State five qualities of potable water.

Answer 7: five qualities  of Potable Water:

  • Potable water should be colorless and odorless.
  • It should be transparent.
  • It should be free from impurities such as suspended solids.
  • It should contain some minerals and salts, necessary for our body and some dissolved gases to add taste.
  • It should be free from harmful microorganisms.

Que: 8. Why is distilled water not recommended as potable water ?

Answer 8: Potable water – The water that is fit for human consumption is called potable water.

Distilled water – It is the purest form of water that is made from potable water for using in chemical reactions and analysis.

Distilled water can not be used as potable water due to the following reasons:-

  • It does not contain any dissolved salts of sodium, calcium, potassium etc. necessary for human health.
  • It does not have any taste.
  • It does not contain any dissolved gases.

Que: 9. State two ways by which a small amount of clear water can be made safe for drinking.

Answer 9: Potable water – The water that is fit for human consumption is called potable water.

The following two ways are the most commonly used methods to make a small amount of clear water safe for drinking

  1. Boiling – boiling water for a few minutes is the most common household technique to get potable water. Water is boiled for 10-15 minutes and then used. This boiling action kills germs and bacteria and precipitates out some dissolved salts as well.
  2. Chemical treatment – this is a relatively new and less time and energy consuming technique. It involves the addition of tablets of alum and halazone (chlorine). The alum precipitates out any remaining salts and halazone tablets release chlorine that disinfects the water.

Que: 10. How is the river water converted into potable water, for a city water supply system ?

Answer 10: SOURCE ⇒ SEDIMENTATION ⇒ FILTRATION ⇒ CHLORINATION ⇒ TO CITY

Potable water- The water that is fit for human consumption is called potable water.

The river water is converted into potable water by following steps –

A. SEDIMENTATION –

  1. The process of settling down suspended impurities present in water is called sedimentation.
  2. The water is collected in a tank and allowed to settle down.
  3. This process can be accelerated by the addition of chemicals like alum and lime to form sticky precipitates that settle down at the bottom of the tank.

B. FILTRATION –

  1. The water after sedimentation is much clear, but still, some suspended impurities are left behind.
  2. To remove these impurities the water is passed through a bed of fine sand, activated charcoal, and gravel to remove the suspended impurities and bad odor.

C. CHLORINATION –

  1. The water after filtration is clear and free from any type of suspended impurities, but it contains germs and bacteria that can cause diseases.
  2. To kill all the germs and bacteria water is treated with chlorine gas. this process is called chlorination of water.

SUMMARY –

  • Water from the source is first subjected to sedimentation.
  • Then the water is filtered to remove any suspended impurities left after sedimentation.
  • Finally to kill germs and bacteria the water is treated with chlorine by the process of chlorination.

— : end of Importance Of Water And Its Resources Class-6th Goyal Brothers Chemistry Solutions ch-4 unit-1 :–-

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