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How will you check with the help of soap powder whether water is hard? - General Science

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प्रश्न

How will you check with the help of soap powder whether water is hard? 

लघु उत्तरीय
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उत्तर

  1. In hard water (from a well or a tube well), soap does not foam but instead creates scum.
  2. As a result, soap loses its cleaning ability. So, using soap, we can determine that the water is hard.
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अध्याय 15: Materials We Use - Exercise [पृष्ठ १०३]

APPEARS IN

बालभारती General Science [English] Standard 7 Maharashtra State Board
अध्याय 15 Materials We Use
Exercise | Q 2.2 | पृष्ठ १०३
बालभारती General Science Integrated [English] Standard 7 Maharashtra State Board
अध्याय 15 Materials we Use
Exercise | Q 2. (b) | पृष्ठ ९७

संबंधित प्रश्न

A student takes about 4 ml of distilled water in four test tubes marked P, Q, R and S. He then dissolves in each test tube an equal amount of one salt in one test tube, namely sodium sulphate in P, potassium sulphate in Q, calcium sulphate in R and magnesium sulphate in S. After that he adds an equal amount of soap solution in each test tube. On shaking each of these test tubes well, he observes a good amount of lather (foam) in the test tube marked

(A) P and Q

(B) Q and R

(C) P, Q and S

(D) P, R and S


Why does micelle formation take place when soap is added to water? Will a micelle be formed in other solvents such as ethanol also?


Distinguish between esterification and saponification reactions of organic compounds.


Give a scientific explanation.

Soap forms a precipitate in hard water. 


Soaps were originally made from ______.


Match the following

1. Soap C6H5 OH
2. Cement CaSO4.2H2O
3. Fertilizers NaOH
4. Gypsum RCC
5. Phenol NPK

Arrange the following statements in correct sequence

  1. Pour that solution into an empty matchbox, soap can be obtained after drying.
  2. Take the necessary quantity of water in a jar.
  3. Then add coconut oil drop by drop and stir it well.
  4. Add concentrated sodium hydroxide in the jar and allow it to cool.
  5. Try this soap to wash your hand kerchief.
  6. Cover your work area with old newspaper.

The alkaline hydrolysis of fatty acids is termed as ______


Soaps are ester of which type of acids?


______ are substances which can undergo chemical changes to produce certain materials.


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