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प्रश्न
Give a scientific explanation.
Soap forms a precipitate in hard water.
उत्तर
When soap is mixed with hard water calcium and magnesium salts of fatty acids are formed. These being water insoluble they form a precipitate and that is why lather is not formed.
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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
A student takes four test tubes marked P, Q, R and S of 25 mL capacity and fills 10 mL of distilled water in each. He dissolves one spoon full of four different salts in each as − KCl in P, NaCl in Q, CaCl2 in R and MgCl2 in S. He then adds about 2 mL of a sample of soap solution to each of the above test tubes. On shaking the contents of each of the test tubes, he is likely to observe a good amount of lather (foam) in the test tubes marked
(a) P and Q
(b) R and S
(c) P, Q and R
(d) P, Q and S
Distinguish between esterfication and saponification reaction with the help of the chemical equations for each.
Mention the essential material (chemicals) to prepare soap in the laboratory. Describe in brief the test of determining the nature (acidic/alkaline) of the reaction mixture of saponification reaction.
Use of synthetic detergents causes pollution of water.
Explain the process of preparation of soap in laboratory.
Describe the structure of a soap molecule with the help of a diagram.
Give the reason of formation of scum when soaps are used with hard water.
Why are soaps not suitable for washing clothes when the water is hard?
Differentiate between:
Detergents and Soaps.
What is the difference between soaps and detergents? State, in brief, the cleansing action of soaps in removing an oily spot from a fabric. Why are soaps not very effective when a fabric is washed in hard water? How is this problem resolved?
What is meant by 'surface activity'?
Write an answer to the following question.
Name three chemicals responsible for the surface activity of various detergents.
Explain why synthetic detergents are superior to soap.
The alkaline hydrolysis of fatty acids is termed as ______
Soaps are ester of which type of acids?
How does soap clean clothes?
______ are substances which can undergo chemical changes to produce certain materials.
The soap molecule has a
- Write the formula and draw electron dot structure of carbon tetrachloride.
- What is saponification? Write the reaction involved in this process.
