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प्रश्न
What is meant by ‘surface activity’?
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उत्तर
The surface activity of a substance is the property by virtue of which it can spread on a surface. For example, soapy water easily spreads on any kind of surface and thus is used for cleaning purposes.
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
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
Fill in the following blank with suitable word:
The sodium salt of a long chain fatty acid is called .............
Which of the two is better for washing clothes when the water is hard: soap or detergent? Give reason for your answer.
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
A student takes 4 mL of distilled water in each of four test tubes I, II, III and IV, and then dissolves an equal amount of four different salts namely NaCl in I, CaCl2 in II, MgCl2 in III and KCl in IV. He then adds 8 drops of the given soap solution to each test tube and shakes the contents of the test tube 10 times. In which test tubes will enough lather (foam) be formed ?
(A) I and II
(B) II and III
(C) I and IV
(D) III and IV
Name three chemicals responsible for the surface activity of various detergents.
What are the two different types of molecules found in the soap?
______ molecules go and join with dirt and oil in the cloth.
