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Question
Explain why often coloured spots are formed on clothes during washing.
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Solution
The laundry, skincare, beauty, and personal hygiene products that we use commonly can cause stains and color changes in our clothes. Toothpaste, perspiration, facial soap, deodorants, hair sprays, strong perfumes with alcohol, and even rain are often the causes of stains on garments. All these stains may eventually dry up, not causing any visible stain; however, age and exposure to heat will cause them to reappear.
RELATED QUESTIONS
Why do soaps not form lather in hard water?
List two problems that arise due to the use of detergents instead of soaps.
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)?
A student took four test tubes P, Q, R and S and filled about 8 mL of distilled water in each. After that he dissolved an equal amount of Na2SO4 in P, K2SO4 in Q, CaSO4 in R and MgSO4 in S. On adding an equal amount of soap solution and shaking each test tube well, a good amount of lather will be obtained in the test tubes:
(a) P and Q
(b) P and R
(c) P, Q and S
(d) Q, R and S
Why is soap not suitable for washing clothes when the water is hard?
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
Distinguish between esterification and saponification reactions of organic compounds.
Explain why soap cannot be used in hard water.
Soaps are ester of which type of acids?
