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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?
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
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
Explain the formation of scum when hard water is treated with soap.
A student requires hard water for an experiment in his laboratory which is not available in the neighbouring area. In the laboratory there are some salts, which when dissolved in distilled water can convert it into hard water. Select from the following groups of salts, a group, each salt of which when dissolved in distilled water will make it hard.
(A) Sodium chloride, Potassium chloride
(B) Sodium sulphate, Potassium sulphate
(C) Sodium sulphate, Calcium sulphate
(D) Calcium sulphate, Calcium chloride
Explain the process of preparation of soap in laboratory.
Why is soap not suitable for washing clothes when the water is hard?
How is soap made? Write a word equation involved in soap making.
Give any two differences between soaps and detergents.
Explain the cleansing action of soap. Draw diagrams to illustrate your answer.
The chemical which is not required for the preparation of soap in the laboratory is:
(a) vegetable oil
(b) baking soda
(c) caustic soda
(d) common salt
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
A student is testing water to know which is best for cleansing purposes with soaps. He would find that the cleansing action of soaps is best when he uses water obtained from
(a) rain
(b) tap
(c) hand pump
(d) pond
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
Give a scientific explanation.
Soap forms a precipitate in hard water.
What is meant by 'surface activity'?
The saponification of a fat or oil is done using _____ solution for hot process.
Arrange the following statements in correct sequence
- Pour that solution into an empty matchbox, soap can be obtained after drying.
- Take the necessary quantity of water in a jar.
- Then add coconut oil drop by drop and stir it well.
- Add concentrated sodium hydroxide in the jar and allow it to cool.
- Try this soap to wash your hand kerchief.
- Cover your work area with old newspaper.
Soaps are ester of which type of acids?
We are using ______ to remove strong stains on the clothes.
In the soap micelles
What are the similarities between Soap and synthetic detergent.
