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 EXPLAIN THE CLEANING ACTION OF SOAPS IN A SYSTEMATIC MANNER.

Asked by Goutam Naik(student) , on 13/3/11

Answers

A spherical aggregate of soap molecules in the soap solution in water is called micelle.When soap is dissolved in water, it forms a colloidal suspension in which the soap molecules cluster together to form spherical micelles. In a soap micelle. the soap molecules are arranged radially with hydrocarbons ends directed inwards and ionic part directed outwards.When a dirty clot is inserted in the solution ten the hydrocarbon part stiks to tthe dirt or oil. With a little agitation the dirt particles get entrapped by the soap micelles and get dispersed in water due to which the soap water gets dirty and the cloth gets cleaned

Posted by T Swetha(student)on 13/3/11

A soap molecule has an ionic part and a non-ionic part. A soap molecule structure is like a tadpole,where its tail indicates the long chain of saturated hydrocarbons(non-ionic)part and the head indicates the ionic part(containing ions).Now, u know that dirty clothes do not get easily cleaned in water by simply rubbing it beacuse it contains some oil molecules or grease molecules which are im-miscible(cannot be mixed)in water.Now here comes the use of soap molecules...

when the soap molecules come in contact with water,the non-ionic part of the soap molecule (hydrocarbon chain)attaches itself to the dirt or the grease because it is miscible in it.The ionic part remains in the water because water is also partially ionic in nature...so you see that "like dissolves the like".these soap molecules gradually surround the dirt particle by dissolving their non-ionic end in it and gradually form michelle(a round structure around the dirt particle) and then they detach the dirt particle and incapsulate(imbed)it in water molecules,making it miscible in water.thus the cloth gets thoroughly cleaned after being rinsed nicely.. : )

A soap molecule has an ionic part and a non-ionic part. A soap molecule structure is like a tadpole,where its tail indicates the long chain of saturated hydrocarbons(non-ionic)part and the head indicates the ionic part(containing ions).Now, u know that dirty clothes do not get easily cleaned in water by simply rubbing it beacuse it contains some oil molecules or grease molecules which are im-miscible(cannot be mixed)in water.Now here comes the use of soap molecules...

when the soap molecules come in contact with water,the non-ionic part of the soap molecule (hydrocarbon chain)attaches itself to the dirt or the grease because it is miscible in it.The ionic part remains in the water because water is also partially ionic in nature...so you see that "like dissolves the like".these soap molecules gradually surround the dirt particle by dissolving their non-ionic end in it and gradually form michelle(a round structure around the dirt particle) and then they detach the dirt particle and incapsulate(imbed)it in water molecules,making it miscible in water.thus the cloth gets thoroughly cleaned after being rinsed nicely.. : )

The cleaning action of soap occurs when oil and grease are absorbed into the hydrophobic centers of soap micelles and are washed away.


cleansing action of soap

fig 7.10 - Cleansing action of soap

Sodium lauryl sulphate is a synthetic detergent present in laundry soaps, toothpastes and shampoos. The formula of sodium lauryl sulphate is CH 3 (CH 2 ) 1 1 SO 4 - Na + . It has a hydrophilic sulphate group and a hydrophobic dodecyl (C 1 2 H 2 5 ) group. These detergent molecules are called 'anionics ' because they have negative charge at the hydrophilic end. There are detergents which are 'cationics ' that is they have positive charge at the hydrophilic end.

thumbs up pleaseeee...

Posted by Vartika(student)on 13/3/11

EXPERT ANSWER

Hi,

We know that soaps and detergents make oil and dirt present in a cloth dissolve in water, thereby making the cloth clean.

Soap has one polar end (the end with sodium or potassium ion) and one non-polar end (the end with fatty acid chain) as shown in the figure. The polar end is hydrophilic in nature i.e., this end is attracted towards water. The non-polar end is hydrophobic, but lipophilic in nature i.e., it is attracted towards hydrocarbons, but not attracted towards water.


A soap molecule

When soap is dissolved in water, its hydrophobic ends attach themselves to dirt and remove it from the cloth, as shown sequentially in the figure that follows.




Diagram representing the cleansing action of soap

First, the molecules of soap arrange themselves in micelle formation and trap the dirt at the centre of the cluster. These micelles remain suspended in water like particles in a colloidal solution. The various micelles present in water do not come together to form a precipitate as each micelle repels the other because of the ion-ion repulsion.

Thus, the dust particles remain trapped in micelles (which remain suspended) and are easily rinsed away with water. Hence, soap micelles remove dirt by dissolving it in water.

Hope this helps.

Best Wishes!

Posted by Shveta Dua(MeritNation Expert)on 14/3/11

This conversation is already closed by Expert

what is this term lipophilic ?

Posted by Goutam Naik(student)on 15/3/11

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