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प्रश्न
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.
उत्तर
Test tube A contains distilled water which is considered as soft water, free from ions like Mg2÷, Ca2+, etc. So, in this case, the length of foam will be the longest(maximum). Test tube B contains underground water which contains ions like Mg2+, Ca2÷, etc. which react with soaps to form salts of fatty acids called scum, which is insoluble in water. So, in this case, the length of foam will be less in comparison to test tube A. Test tube C contains distilled water with CaSO4, which contains Ca2÷ ions which react with soaps to form salts of fatty acids called scum, which is insoluble in water. So, in this case, also, the length of foam will be less in comparison to test tube A.
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संबंधित प्रश्न
List two problems that arise due to the use of detergents instead of soaps.
While preparing soap a small quantity of common salt is generally added to the reaction mixture of vegetable oil and sodium hydroxide. Which one of the following may be the purpose of adding common salt?
(A) To reduce the basic nature of the soap
(B) To make the soap neutral
(C) To enhance the cleansing power of the soap
(D) To favour the precipitation of the soap
A student takes about 4 ml of distilled water in four test tubes marked P, Q, R and S. He then dissolves in each test tube an equal amount of one salt in one test tube, namely sodium sulphate in P, potassium sulphate in Q, calcium sulphate in R and magnesium sulphate in S. After that he adds an equal amount of soap solution in each test tube. On shaking each of these test tubes well, he observes a good amount of lather (foam) in the test tube marked
(A) P and Q
(B) Q and R
(C) P, Q and S
(D) P, R and S
State one advantage of soaps over detergent.
Explain the process of preparation of soap in laboratory.
Describe the structure of a soap molecule with the help of a diagram.
What is the difference between the chemical composition of soaps and detergents? State in brief the action of soaps in removing an oily spot from a shirt. Why are sops not considered suitable for washing where water is hard?
Soap is a salt of ______ and sodium hydroxide.
What are the two different types of molecules found in the soap?
______ to remove strong strains on the clothes.
