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प्रश्न
How will you check with the help of soap powder whether water is hard?
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उत्तर
- 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.
संबंधित प्रश्न
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
People use a variety of methods to wash clothes. Usually after adding the soap, they ‘beat’ the clothes on a stone, or beat it with a paddle, scrub with a brush or the mixture is agitated in a washing machine. Why is agitation necessary to get clean clothes?
Explain the formation of scum when hard water is treated with soap.
State one use of saponification process.
Differentiate between:
Detergents and Soaps.
Answer the following question.
In three test tubes A, B, and C, three different liquids namely, distilled water, underground water and distilled water in which a pinch of calcium sulphate is dissolved, respectively are taken. Equal amount of soap Answer is added to each test tube and the contents are shaken. In which test tube will the length of the foam (lather) be longest? Justify your answer.
Name three chemicals responsible for the surface activity of various detergents.
Arrange the following statements in correct sequence
- Pour that solution into an empty matchbox, soap can be obtained after drying.
- Take the necessary quantity of water in a jar.
- Then add coconut oil drop by drop and stir it well.
- Add concentrated sodium hydroxide in the jar and allow it to cool.
- Try this soap to wash your hand kerchief.
- Cover your work area with old newspaper.
How does soap clean clothes?
______ are substances which can undergo chemical changes to produce certain materials.
