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प्रश्न
Explain why soap cannot be used in hard water.
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उत्तर
Soaps cannot be used in hard water because they lose their cleansing property when used with it. Soaps do not form lather with hard water and instead form scum, as a result of which they lose their cleansing property.
संबंधित प्रश्न
Describe in brief the cleansing action of 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
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
Explain the formation of scum when hard water is treated with soap.
Distinguish between esterfication and saponification reaction with the help of the chemical equations for each.
What is saponification? Write the chemical equation of the reaction involved in this process. Name all the substances which take part in this process and also those which are formed.
In a soap micelle, the soap molecules are arranged radially with:
(a) ionic ends directed towards the centre and hydrocarbon ends directed outwards
(b) hydrocarbon ends directed towards the centre and ionic ends directed outwards
(c) both ionic ends and hydrocarbon ends directed toward the centre
(d) both hydrocarbon ends and ionic ends directed outwards
The chemical mostly used in the preparation of most of the soaps we use is
(a) Sodium chloride
(b) Potassium hydroxide
(c) Sodium hydroxide
(a) Potassium chloride
TFM in soaps represents ______ content in soap.
______ are substances which can undergo chemical changes to produce certain materials.
