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प्रश्न
Why does micelle formation take place when soap is added to water? Will a micelle be formed in other solvents such as ethanol also?
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उत्तर
- Soaps are molecules in which the two ends have differing properties, one is hydrophilic, that is, it interacts with water, while the other end is hydrophobic, that is, it interacts with hydrocarbons.
- When soap is at the surface of water, the hydrophobic ‘tail’ of soap will not be soluble in water, and the soap will align along the surface of water with the ionic end in water and the hydrocarbon ‘tail’ protruding out of water.
- Inside water, these molecules have a unique orientation that keeps the hydrocarbon portion out of the water. Thus, clusters of molecules in which the hydrophobic tails are in the interior of the cluster and the ionic ends are on the surface of the cluster. This formation is called a micelle.
- Soap in the form of a micelle is able to clean, since the oily dirt will be collected in the centre of the micelle. The micelles stay in solution as a colloid and will not come together to precipitate because of ion-ion repulsion.
- Thus, the dirt suspended in the micelles is also easily rinsed away. The soap micelles are large enough to scatter light. Hence a soap solution appears cloudy.
- Since ethanol is not as polar as soap, so micelles will not be formed in other solvents such as ethanol.
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
Hard water is not available for an experiment. Some salts are given below :
(I) Sodium chloride
(II) Sodium sulphate
(III) Calcium chloride
(IV) Calcium sulphate
(V) Potassium chloride
(VI) Magnesium sulphate
Select from the following group of these salts, each member of which may be dissolved in water to make it hard.
(A) I, II, V
(B) I, III, V
(C) III, IV, VI
(D) II, IV, VI
Explain the formation of scum when hard water is treated with soap.
A student took four test tubes P, Q, R and S and filled about 8 mL of distilled water in each. After that he dissolved an equal amount of Na2SO4 in P, K2SO4 in Q, CaSO4 in R and MgSO4 in S. On adding an equal amount of soap solution and shaking each test tube well, a good amount of lather will be obtained in the test tubes:
(a) P and Q
(b) P and R
(c) P, Q and S
(d) Q, R and S
Distinguish between esterfication and saponification reaction with the help of the chemical equations for each.
Explain esterification reaction with the help of a chemical equation. Describe an activity to show esterification.
Why have detergents replaced soap as a washing agent?
Which of the two is better for washing clothes when the water is hard: soap or detergent? Give reason for your answer.
Describe the structure of a soap molecule with the help of a diagram.
Consider the following oils :
(I) Mobil oil
(II) Castor oil
(III) Turpentine oil
(IV) Kerosene
(V) Mustard oil
(VI) Coconut oil
Which of these can be used for prepartion of soap?
(a) I, II, III, VI
(b) II, V, VI
(c) II, III, V, VI
(d) II, III, VI
Why are soaps not suitable for washing clothes when the water is hard?
Explain the action of soap in removing an oily spot from a piece of cloth.
Name three chemicals responsible for the surface activity of various detergents.
Explain why synthetic detergents are superior to soap.
Explain why often coloured spots are formed on clothes during washing.
TFM in soaps represents ______ content in soap.
Soaps are ester of which type of acids?
______ are substances which can undergo chemical changes to produce certain materials.
What are the similarities between Soap and synthetic detergent.
