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Question
How will you check with the help of soap powder whether water is hard?
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Solution
- In hard water (from a well or a tube well), soap does not foam but instead creates scum.
- As a result, soap loses its cleaning ability. So, using soap, we can determine that the water is hard.
RELATED QUESTIONS
In the neighbourhood of your school, hard water required for an experiment is not available. Select from the following group of salts available in your school, a group each member of which, if dissolved in distilled water, will make it hard:
(a) Sodium chloride, calcium chloride
(b) Potassium chloride, sodium chloride
(c) Sodium chloride, magnesium chloride
(d) Calcium chloride, magnesium chloride
What change will you observe if you test soap with litmus paper (red and blue)?
The sodium salt of a long chain fatty acid is called ______.
Why have detergents replaced soap as a washing agent?
What is the advantage of detergents over soaps for washing clothes?
The soap molecule has a ______.
A student is testing water to know which is best for cleansing purposes with soaps. He would find that the cleansing action of soaps is best when he uses water obtained from
(a) rain
(b) tap
(c) hand pump
(d) pond
Give a scientific explanation.
Soap forms a precipitate in hard water.
Soaps were originally made from ______.
Analogy:
Used to join components: Adhesives:: Clean the body ______.
