Tag: water: a precious resource

Questions Related to water: a precious resource

Which scientist showed that water is made up of hydrogen and oxygen?

evs water: a precious resource importance of water let's play with water water and its properties water resources and conservation

  1. Antonie Lavoiser

  2. Dalton

  3. Henry Cavendish

  4. Carl Scheele

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Correct Option: C
Explanation:

Henry Cavendish showed that water is made up of hydrogen and oxygen.

What is the no. of molecules of water in $CuSO _4$?

evs water: a precious resource importance of water let's play with water water and its properties water resources and conservation

  1. 3

  2. 4

  3. 5

  4. 6

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Correct Option: C
Explanation:

The number of molecules of water is 5. The formula is $CuSO _4. 5H _2O$.

What is the colour of $CuSO _4.5H _2O$?

evs water: a precious resource importance of water let's play with water water and its properties water resources and conservation

  1. Blue

  2. Black

  3. Green

  4. Brown

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Correct Option: A
Explanation:

The colour of hydrated copper sulphate is blue.

Addition of water to $CoCl _2$ changes colour from blue to:

evs water: a precious resource importance of water let's play with water water and its properties water resources and conservation

  1. red

  2. pink

  3. violet

  4. green

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Correct Option: B

Removal of water from $CuSO _4.5H _2O$ changes colour from blue to:

evs water: a precious resource importance of water let's play with water water and its properties water resources and conservation

  1. black

  2. green

  3. white

  4. brown

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Correct Option: C
Explanation:

The colour of anhydrous copper sulphate is white.

Saline water from the oceans consists of ______ percentage of the total water present on the Earth.

evs water: a precious resource importance of water let's play with water water and its properties water resources and conservation

  1. $92.5$

  2. $93.7$

  3. $99.8$

  4. $79.5$

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Correct Option: B

$H _2S$ reacts with $H _2SO _4$, the product may not be 

evs water: a precious resource importance of water let's play with water water and its properties water resources and conservation

  1. $H _2O$

  2. $SO _2$

  3. $S$

  4. $H _2O _2$

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Correct Option: A

The earth appears blue from outer space because:

evs water: a precious resource importance of water let's play with water water and its properties water resources and conservation

  1. of the forest

  2. of the sky

  3. of the water

  4. all of these

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Correct Option: C
Explanation:

The earth appears blue from outer space because 70% of the earth's surface contains water, i.e., water bodies like oceans, seas, rivers, lakes, etc.

Which property of water is used while washing clothes?

evs water: a precious resource importance of water let's play with water water and its properties water resources and conservation

  1. odour

  2. colour

  3. solubility

  4. surface tension

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Correct Option: D
Explanation:

The property of the surface of a liquid that allows it to resist an external force, due to the cohesive nature of its molecules is called surface tension. while washing clothes, detergents reduce the surface tension of the water molecule which causes the formation of foam and cleaning of clothes. 


Option D is correct. 

A sample of water contains sodium chloride and magnesium chloride. Which of the following is not applicable to this?

evs water: a precious resource importance of water let's play with water water and its properties water resources and conservation

  1. It is hard water because magnesium chloride is dissolved in it.

  2. It is hard water because sodium chloride is dissolved in it.

  3. A is hard water because it given only small amount of froth.

  4. It is a hard water because it leaves solid residue on evaporation which given test for $Mg^{2+}$.

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Correct Option: C
Explanation:

Hard water contains chlorides, carbonates and bicarbonates of sodium and magnesium ions which combine with soap micelles and do not give lather with soap.