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प्रश्न
What change will you observe if you test soap with litmus paper (red and blue)?
उत्तर
Since soap is basic in nature, it will turn red litmus blue. When soap is dissolved in water, the solution becomes alkaline due to the formation of alkali NaOH or KOH. The solution changes the colour of red litmus to blue, but it does not change the colour of blue litmus.
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संबंधित प्रश्न
Differentiate between Toilet soap and Laundry soap.
Why do soaps not form lather in hard water?
List two problems that arise due to the use of detergents instead of soaps.
Which of the following sets of materials can be used for conducting a saponification reaction for the preparation of soap?
(a) Ca(OH)2 and neem oil
(b) NaOH and neem oil
(c) NaOH and mineral oil
(d) Ca(OH)2 and mineral oil
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?
Why does micelle formation take place when soap is added to water? Will a micelle be formed in other solvents such as ethanol also?
Fill in the following blank with suitable word:
............. is better than soap for washing clothes when the water is hard.
State one advantage of soaps over detergent.
Why is common salt (sodium chloride) added during the preparation of soap?
The soap molecule has a ______.
The chemical which is not required for the preparation of soap in the laboratory is:
(a) vegetable oil
(b) baking soda
(c) caustic soda
(d) common salt
Give the reason of formation of scum when soaps are used with hard water.
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
What are detergents chemically? List two merits and two demerits of using detergents for cleansing. State the reason for the suitability of detergents for washing, event in the case of water having calcium and magnesium ions.
What is meant by 'surface activity'?
Explain why soap cannot be used in hard water.
Explain why often coloured spots are formed on clothes during washing.
The saponification of a fat or oil is done using _____ solution for hot process.
TFM in soaps represents ______ content in soap.
