National Science Olympiad Forum By SOF Olympiad Trainer - Page 419

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Subject :NSO    Class : Class 5

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Subject :NSO    Class : Class 8

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Subject :NSO    Class : Class 3

Ans 1:

Class : Class 7
B

Ans 2:

Class : Class 7
it is sure sure B

Ans 3:

Class : Class 3
B

Ans 4:

Class : Class 3
B

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Subject :NSO    Class : Class 3

Ans 1:

Class : Class 7
D

Ans 2:

Class : Class 7
ans:D

Ans 3:

Class : Class 7
ans:D

Ans 4:

Class : Class 3
C

Ans 5:

Class : Class 3
D

Ans 6:

Class : Class 4
wtf

Ans 7:

Class : Class 3
D

Ans 8:

Class : Class 7
ans:D

Ans 9:

Class : Class 4
d

Ans 10:

Class : Class 7
D non of these

Ans 11:

Class : Class 7
Why answer is not D.

Ans 12:

Class : Class 4
ans is d

Ans 13:

Class : Class 3
how??

Ans 14:

Class : Class 7
ans:D

Ans 15:

Class : Class 3
d

Ans 16:

Class : Class 8

Ans 17:

Class : Class 3
none of these

Ans 18:

Class : Class 3
D

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Subject :NSO    Class : Class 8

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Subject :NSO    Class : Class 8

While demonstrating the reactivity order of different metals, a science teacher arranged the following apparatus :

Select the correct statement regarding this activity.

A A chemical change will take place in all the three beakers if metal Y is magnesium.
B There will be no change in colour of solution if metal Y is aluminium.
C The reactivity order of given metals is Y > Zinc > Iron > Copper if reaction occurs in beaker (III).
D All of these


Ans 1:

Class : Class 6

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Subject :NSO    Class : Class 6

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Subject :NSO    Class : Class 5

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Subject :NSO    Class : Class 5

Ans 1:

Class : Class 5
The correct option should be - 1-3-2 ( Sedimentation - Filtration - Chlorination )This option is not given. Sedimentation - All the particles settle down as gravity pulls the heavier sediments down.Filtration - It removes the sediments from the water.Chlorination - Process of adding chlorine to water and removing the parasites,bacteria and viruses. Now the water is purified.

Ans 2:

Class : Class 7
the order should be 1-3-2 . there is no option like that. what are these SOF people

Ans 3:

Class : Class 5
The correct order is 1-3-2 and there is no option like that .So,I think that it might be a printing error.

Ans 4:

Class : Class 5
please no printing errors

Ans 5:

Class : Class 3

Ans 6:

Class : Class 9

Ans 7:

Class : Class 5
(i) Sedimentation - Sedimentation is a physical water purification process using gravity to remove suspended solid impurities from water. The water is allowed to stand till the suspended solid impurities, which are heavier than water, are pulled down by gravity and settle at the bottom of the container.(ii) Chlorination - Chlorination is the process of adding chlorine, or chlorine compounds such as sodium hypochlorite, to drinking water to disinfect it and kill germs. The addition of chlorine will also oxidize any iron, manganese and/or hydrogen sulphide that are present, so that they too can be removed in the filtration process later on.(iii) Filtration - Filtration is a process of water purification, which is used to separate solid impurities from water by using a filter medium that allows the water to pass through but not the solid impurities. These solid impurities are not heavy, so they do not settle at the bottom, but remain suspended. So, a filter is used to trap them.So, to purify water, it must go through sedimentation (i) first, so that heavier and larger size impurities like sand and dirt, are allowed to settle at the bottom of the container and are removed first. Next, water must go through chlorination (ii), so that bacteria and germs present in water are killed. Any iron, manganese and/or hydrogen sulphide, if present, also get oxidized by chlorine. These can be removed later by the filtration (iii) process, along with other suspended impurities.Hence, the right answer is Option D.

Ans 8:

Class : Class 4
the correct order is 1,3,2 but there is no option like that but if you look at option A you'll find the correct order in a descending order (from back) so if there is no option like 1,3,2 then A should be correct

Ans 9:

Class : Class 5
Correct option should be 1, 3, 2.

Ans 10:

Class : Class 3

Ans 11:

Class : Class 6
1-3-2 is the correct order as first we should remove all the insoluble impurities and the the soluble impurities.

Ans 12:

Class : Class 9

Ans 13:

Class : Class 4

Ans 14:

Class : Class 5
correct order is 1-3-2 but there is no option

Ans 15:

Class : Class 8
The correct order is 1-3-2 but there's no option having it

Ans 16:

Class : Class 6

Ans 17:

Class : Class 7

Ans 18:

Class : Class 5
the order is not 1-2-3. it is 1-3-2. but there is no option

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Subject :NSO    Class : Class 4

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