STD-4, CHAPTER-9: SAFE HANDLING AND STORAGE OF WATER, EXERCISE QUESTION ANSWERS

A.     FILL IN THE BLANKS.

1.      Water, which is fit for drinking, is called ______.

Ans: potable water

2.      Ground water is not fit for drinking because it contains ______ and _______.

Ans: dirt and germs

3.      _____ removes dust from water.

Ans: filtration

4.      ______ and _____ kill germs present in water.

Ans: boiling and chlorination

5.      Water should always be stored in ____ and ____ utensils.

Ans: clean and covered

B.      WRITE TRUE OR FALSE FOR THE FOLLOWING STATEMENTS.

 

1.      We should always store drinking water in covered clean containers.    True

2.      We can drink water that has been stored for many days.                        False

3.      We need to purify water before drinking it.                                                True

4.      We can allow water to stagnate around our house.                                  False

5.      We should use a ladle to take out water from a container.                     True

 

C.      TICK THE CORRECT OPTION.

 

1.      Germs, present in water, may be killed by-

(a)   Simple filtration

(b)   Storing it in covered containers

(c)    Storing it for many days

(d)   Chlorination

      Ans: chlorination

2.      By drinking unclean water, one may get a disease like-

(a)   malaria

(b)   dengue

(c)    chikungunya

(d)   jaundice    

      Ans: jaundice

3.      Dust and other suspended particles present in unclean water can be removed-

(a)   boiling

(b)   keeping it in a fridge

(c)    filtration

(d)   chlorination 

       Ans: filtration

4.      Our body requires, and uses, water for-

(a)   breathing

(b)   digestion of food

(c)    preparation of food

(d)   transpiration           

      Ans: digestion of food

D.     ANSWER THE FOLLOWING QUESTIONS IN BRIEF.

 

1.      State the meaning of the term ‘potable water’.

Ans: Water, which is fit for drinking, is called potable water.

2.      Name any two diseases that can be caused by drinking unclean water.

Ans: The two diseases that can be caused by drinking unclean water are, jaundice, diarrhea, dysentery and cholera.     

3.      Name the diseases which are spread by mosquitoes.

Ans: The diseases which are spread by mosquitoes are, malaria, dengue and chikungunya.

4.      How does boiling help in making water safer for drinking?

Ans: Boiling kills the germs present in water, making it safer for drinking.

5.      Name two methods of purification of water.

Ans: Two methods of purification of water are, boiling and filtration.

6.      State any two ways of safe handling of drinking water.

Ans: Two ways of safe handling of drinking water are,

(i) Water should always be stored in clean and covered containers.

(ii) We should use a ladle to take out water from a container

E.      ANSWER THE FOLLOWING QUESTIONS.

 

1.      Why should water be purified before drinking?

Ans: Water from all sources is not fit for drinking. Drinking unclean water can cause diseases like jaundice, diarrhea, dysentery and cholera. Thus, we should purify water before drinking it.

2.      What is chlorination? How does it purify water?

Ans: (i) Chlorination is a method to purify water by adding a correct small amount of chlorine in it.

(ii) This kills the germs and makes water fit for drinking.

 

3.      Why is the traditional method of filtration not completely sufficient for making water fit for drinking?

Ans: Traditional method of filtration can remove dust and other suspended particles from water. However, this method does not remove germs. Thus, the traditional method of filtration is not completely sufficient for making water fit for drinking.

4.      Why should we not allow water to stagnate around our houses?

Ans: (i) Dirty and stagnant water is a major cause of diseases.

(ii) It becomes a breeding place for mosquitoes.

(iii) Diseases like malaria, dengue and chikungunya will be spread.

So, we should not allow water to stagnate around our houses.

5.      State two ways that can be used to prevent breeding of mosquitoes in room coolers.

Ans: Two ways to prevent breeding of mosquitoes in room coolers are,

(i) Change water in the room coolers after every 3-4 days.

      (ii) If the water cannot be changed, two spoons of kerosene should be put in it.