Water As Universal Solvent ICSE Class-6th Goyal Brothers Chemistry Solutions Chapter-4 Unit-2

Water As Universal Solvent, Reasons For Its Pollution And Its Prevention ICSE Class-6th Goyal Brothers Chemistry Solutions Chapter-4 (unit-2). We Provide Step by Step Answers of Objective, True False , Fill in the blanks, Match the following , Study Questions of Chapter- 4, Water, Unit-1 (Water As Universal Solvent, Reasons For Its Pollution And Its Prevention). Visit official Website  CISCE  for detail information about ICSE Board Class-6.

Water As Universal Solvent, ICSE Class-6th Goyal Brothers

Ch-4 Unit-2 Reasons For Its Pollution And Its Prevention 

Board ICSE
Class 6th
Subject Chemistry
Book Name Goyal Brothers
Chapter-4 Water
Unit-2 Water As Universal Solvent, Reasons For Its Pollution And Its Prevention
Topic Solution of exercise questions
Session 2023-24

Water As Universal Solvent, Reasons For Its Pollution And Its Prevention ICSE Class-6th Goyal Brothers

Chemistry Solutions Chapter-4 Unit-2

OBJECTIVE TYPE QUESTIONS

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

List : Solubility, polluted, latent, pit, solute

1. A substance which dissolves in water or any other liquid is called solute.

2. latent heat of ice is 80 calories per gram.

3. polluted water can cause diseases like dysentery and cholera.

4. pit latrines can control water pollution caused by human beings in the open fields.

5. The amount of solute which dissolves in 100 g water at a particular temperature to form a saturated solution is called its Solubility.

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

1. The amount of solute which dissolved in 1000 g of water to form a saturated solution is called its solubility.

Answer: The amount of solute which dissolved in 100 g of water to form a saturated solution is called its solubility.

2. The latent heat of steam is 80 calories per gram.

Answer: The latent heat of ice is 80 calories per gram.

3. Cholera is a diseases caused due to air pollution.

Answer: Cholera is a diseases caused due to water pollution.

4. Use of excessive pesticides do not cause pollution of natural water.

Answer: Use of excessive pesticides do not cause pollution of river water.

5. Concentration of dissolved salts in sea water increases every year, because the rivers discharge in it more dissolved salts.

Answer: Concentration of dissolved salts in sea water increases every year, because the rainwater discharge in it more dissolved salts.

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

Column A Column B
1. A disease caused by water pollution. (a) 540 calories
2. Washing down of excessive pesticides and fertilizers in river water. (b) Cholera
3. Amount of heat required to convert 1 g of water at 100°C into steam at 100°C (c) Carbon dioxide
4. Amount of heat required to convert 1 g of ice at 0°C into water at 0°C. (d) Water pollution
5. A gas which dissolves in rainwater. (e) 80 calories

Answer:

Column A Column B
1. A disease caused by water pollution. (a) Cholera
2. Washing down of excessive pesticides and fertilizers in river water. (b) Water pollution
3. Amount of heat required to convert 1 g of water at 100°C into steam at 100°C (c) 540 calories
4. Amount of heat required to convert 1 g of ice at 0°C into water at 0°C. (d) 80 calories
5. A gas which dissolves in rainwater. (e) Carbon dioxide

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

Statement True/False
1. Common salt is the solute in the common salt solution.
2. Pit latrines help in controlling water pollution caused by human beings by defecating in the open.
3. One gram of water at 100°C, needs 80 calories of heat, so as to change into steam at 100°C.
4. A saturated solution of sugar at room temperature can dissolve more sugar at a higher temperature.
5. Use of natural pesticides reduces water pollution.

Answer:

Statement True/False
1. Common salt is the solute in the common salt solution. T
2. Pit latrines help in controlling water pollution caused by human beings by defecating in the open. T
3. One gram of water at 100°C, needs 80 calories of heat, so as to change into steam at 100°C. F
4. A saturated solution of sugar at room temperature can dissolve more sugar at a higher temperature. F
5. Use of natural pesticides reduces water pollution. T

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

1. The product obtained when a solid substance dissolves in a liquid is called

(a) solvent

(b) solute

(c) solution

(d) saturated solution

Answer: option (c) solution is correct.

2. A salt solution which cannot dissolve more of a solute at a given temperature is called.

(a) solution

(b) saturated solution

(c) unsaturated solution

(b) supersaturated solution

Answer: option (b) saturated solution is correct.

3. The polluted water can cause the disease of :

(a) malaria

(b) diarrhea

(c) cancer

(d) heart disease

Answer: option (b) diarrhea is correct.

4. Which disease is not caused by polluted water ?

(a) diarrhea

(b) jaundice

(c) malaria

(d) typhoid

Answer: option (c) malaria is correct.

5. A substance which dissolves very little or do not dissolve in water is called a/an

(a) soluble substance

(b) insoluble substance

(c) non-reactive substance

(d) anti-solute

Answer: option (b) insoluble substance is correct.

Study Questions

Water As Universal Solvent, Reasons For Its Pollution And Its Prevention ICSE Class-6th Goyal Brothers Chemistry Solutions Chapter-4 Unit-2

Question: 1. Define the following terms and support your answer by one example

(a) Solute

Answer: (a)Solute: It is the substance that is present in small amounts in a solution. The solid substance that will dissolve in a liquid is known as the solute.

  • In the example of sugar in water, sugar is solute.
(b) Solvent

Answer: (b) Solvent: It is the substance that is present in large amounts in a solution. The liquid in which a solute substance will dissolve is known as the solvent.

  • In the example of sugar in water, water is a solvent.
(c) Solution

Answer: (c) Solution: These are homogeneous mixtures of two or more than two components.

  • Homogeneous means the uniformity of composition and properties is the same throughout the mixture.
  • When a solid substance is dissolved in a solution it results in the formation of liquid solutions.
  • Sugar in water(H2O) is an example of a solid in a liquid solution.
(d) Saturated solution

Answer: (d) Saturated solution: It is the type of solution in which no more solute can be added at any given temperature.

  • For example, In saturated solutions of sugar in water, no more sugar can be added.
(e) Solubility of solution

Answer: (e) Solubility of solution: The maximum amount of solute that can dissolve in a known quantity of solvent at a certain temperature is its solubility.

Question: 2. State four conditions for the formation of solution.

Answer: The four essential conditions for the formation of a solution are –

1. Number of substances – There should be a minimum of two substances that are readily soluble in each other. The substance in greater quantity is called a solvent and the substance in lesser quantity is called a solute.

2. Mixing – The solution should be stirred continuously to ensure the proper dissolving of a solute in the solvent.

3. State of solute –

  • The solute if solid should be in the form of fine powder to dissolve it easily.
  • If the solute is liquid then it should be properly mixed with a solvent.
  • If the solute is gas then it should be passed through a delivery tube while keeping the container covered.

4. Temperature – The temperature of the solvent should be higher than that of the solute as it increases the solubility of the solute in the solvent.

Question: 3. Why is water called ‘universal solvent’?

Answer: Water is called a ‘universal solvent’ because water can dissolve much more substances than any other liquid found in nature but water cannot dissolve every substance. For example- water cannot dissolve fats, waxes, and hydroxides due to the low solubility of oppositely charged particles.

Question: 4. Briefly explain the importance of dissolved gases in water.

Answer: The importance of dissolved gases can be explained by the following points –

1. Human consumption –

  • The dissolved gases in water give it a particular taste.
  • oxygen gas kills some germs that can cause diseases.

2. For the survival of aquatic organisms –

  • Dissolved gases like oxygen are necessary for the respiration of organisms living in the water.
  • Carbon dioxide gas is essential as raw material for photosynthesis.

3. For industrial use –

  • Carbon dioxide gas is dissolved in soft drinks to create a fizz.
  • In the production of chemicals like hydrochloric acid and many more.

Question: 5. How is water pollution caused by human defecation in the open? How is this problem solved?

Answer: Pollution caused by human defecation in the open:

  • In villages or underdeveloped areas of the country people generally defecate in open fields due to the unavailability of proper toilets and poverty.
  • When this excreta is washed away by water due to rainfall for surface runoff, this excreta enters the rivers and streams and pollute it making the water unfit for drinking.
  • This polluted water if consumed by humans may cause diseases like cholera, diarrhea, typhoid etc.

Question: 6. How is water pollution caused by agricultural practices? Suggest ways to minimize water pollution by the agricultural practices.

Answer: Water pollution caused by agricultural practices

  1. The excessive use of fertilizers and pesticides on crops results in the washing away of these toxic chemicals into rivers and other water bodies and thus polluting them.
  2. These toxic chemicals sometimes get washed away due to rain and percolate through the soil and reach groundwater making it unfit for human use.

Ways to minimise water pollution by agricultural practices

  1. The use of chemical pesticides and fertilizers should be kept to a minimum.
  2. The use of natural pesticides like citronella and manure should be encouraged.
  3. Modern irrigation techniques like drip irrigation should be employed to prevent the percolation of toxic chemicals into groundwater.

Question: 7. Find the odd one out. Give a reason for your answer.

(a) Diarrhea, jaundice, malaria and typhoid

Answer: (a) Malaria: Malaria is caused because of a microorganism called plasmodium which is transmitted by the bite of a female anopheles mosquito.

(b) Spring water, distilled water, river water and rainwater.

Answer: (b) Distilled water: Distilled water is an artificially obtained form of water and does not contain any impurities or dissolved gases.

(c) Seas, lakes, ponds and rivers.

Answer: (c) Sea is the odd one out of the given options.

  • As seawater is water containing salt in it.
  • Whereas all other options i.e. ponds, lakes, and rivers are freshwater habitats and do not contains salt in them.
(d) Sedimentation, decantation, filtration and defecation.

Answer: (d) defecation: It is the process by which waste is removed from the body. This process adds to pollution. Others are separation methods.

(e) Sewer water, chlorinated water, river water and waste water from factories.

Answer: (e) Chlorinated water: Chlorinated water is pure and potable water fit for human consumption. Others are not pure to use it as potable.

Question: 8. (a) Define conservation of water

Answer: (a) Conservation of water -The proper and smart use of water and preventing the waste of this essential resource is called the conservation of water. For example – repairing leaking taps and pipes, using techniques like rainwater harvesting. etc. represents conservation of water.

(b) State the ways to reduce water consumption at home.

Answer: (b)Several ways to reduce water consumption at home:

  • Keep the tap closed when not in use.
  • Check for openings or leaks in water distribution pipes.
  • Make sure to use collected rainwater for gardening or washing purpose.
  • Always have a measure of how many buckets of water are wasted in a day and try to reduce.
  • Do not run more water than necessary while washing and cleaning clothes, utensils, etc.
  • Do not prolong your bathing. Go for a quick shower rather than wasting buckets of water
  • Rainwater harvesting is one of the best methods used for conserving water. There are different methods used to preserve rainwater instead of getting it wasted.

— : end of Water As Universal Solvent, Reasons For Its Pollution And Its Prevention ICSE Class-6th Goyal Brothers Chemistry Solutions Chapter-4 Unit-2 :–-

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