Create your account now. Signup with Email. Gender Male Female. Create Account. Already Have an Account? All you need of Class 10 at this link: Class The Theory Soaps and detergents are essential to personal and public health. Example : Oleic acid C 17 H 33 COOH If the fatty acid has a single carbon-carbon double bond in the molecule, it is known as a mono-unsaturated fatty acid.
SOAP Soaps are sodium or potassium salts of long chain fatty acids. Types of Soap Depending upon the nature of alkali used in the production of soap, they are classified into two types. Hard soap Soft soap In aqueous solution, soap ionises to form alkali ions. Learning Outcomes Students understand the terms: soap, saponification, salting out, hard soap and soft soap. Students identify the materials which are required for the preparation of soap. Students understand the use of common salt in saponification process.
Students understand the alkalies required for the preparation of hard and soft soaps. Students understand the procedure of saponification process. Students acquire the skill to perform the preparation of soap in a real lab. Vigorously stir the mixture using a glass rod.
Touch the beaker from outside. It is observed that the beaker is warm. Place the beaker on a wire gauze placed over a tripod stand. Heat the beaker using a Bunsen burner till the mixture become a whitish paste. Remove the beaker from the flame and allow it to cool.
Dip a red litmus paper in the suspension formed. When dipped in the suspension, the red litmus paper changes its colour to blue. Dip a blue litmus paper in the suspension.
The colour of blue litmus paper remains the same. To the above suspension, add 15g of common salt and stir it well with a glass rod. After adding common salt, soap in the suspension gets precipitated out as solid. Take a filter funnel and place a filter paper in it and fix it in a stand. Place a beaker below the funnel. Pour the contents of the beaker into the funnel over a glass rod and filter the contents of the beaker.
After filtration, soap is left behind in the filter paper. Transfer the soap into another filter paper using a spatula and dry it by pressing with another filter paper. Then, cut it into desired shape with a knife. Simulator Procedure: To start the simulator, click on the measuring cylinder containing 25 ml coconut oil to pour it into the beaker. Click on the glass rod to stir the mixture. Click on the information icon to see the inference. Turn on the burner by clicking on the 'knob' of the burner.
Click on the beaker to place it over the Bunsen burner and heat it. Click on the beaker to place it back from the burner for allowing it to cool. Turn off the burner by clicking on the 'knob' of the burner. Click on the red litmus paper to dip it into the soap suspension.
Click on the blue litmus paper to dip it into the soap suspension. Click on the watch glass containing common salt to add it into the soap suspension. Click on the beaker to filter the contents. Click on the spatula to take soap from the funnel. Click on the filter paper to dry the soap. You can redo the experiment anytime by clicking on the 'Reset' button. Red litmus paper changed colour to blue when dipped in suspension. Blue litmus paper was not affected by the suspension.
After adding common salt, the soap in suspension form precipitated out as solid. Conclusions: The reaction between vegetable oil and sodium hydroxide solution is exothermic in nature because heat is liberated during the reaction. The white suspension formed is made up of soap and glycerol.
The process of formation of soap is called saponification. Test using red and blue litmus papers shows that soap suspension is basic in nature and not acidic in nature.
The process of precipitation of soap from the suspension is called salting out. Precautions: Do not touch the NaOH solution with bare hands as it may burn the skin. Do not breathe the fumes of NaOH or let the fumes get in your eyes. Keep the windows of the laboratory open. The mixture of oil and alkali should be stirred thoroughly. It is necessary to stir the soap solution after adding common salt to it, in order to precipitate out the soap in solid form.
All organic acid contain the RCOOH functional group, where R is the shorthen notation for the complex hydrocarbon which famously known as alkyl group. The term for R is used because the group can be very large and for the addition for each chain has a litter effect for the chemical reactivity. A soap is the sodium or potassium salt of a long chain fatty acid. The fatty acid usually contain 12 to 18 carbon atoms which can be expressed as term R.
Furthermore, the hydrocarbon chain in the soap may contain saturated and unsaturated chains. Sodium salts are usually solid therefore, most bars of soap are sodium salts. While potassium salts are the basis of liquid soaps, shaving cream, and greases.
Triglycerides is formed by the combination of three molecules of fatty acid which are fats and vegetable oils. Saponification is a process that produce soap usually from fats and lye. In the other words, saponification involves base hydrolysis of triglycerides, which are esters of fatty acid to produce a product which is sodium salt od a carboxylate. Besides, saponification processes also produce glycerol.
Since the cleansing action of soaps depend upon the fact that they ionize readily in water,. As the conclusion, the synthetic detergent were developed to overcome this kind of problems. The synthetic detergent form micelles and cleanse in the same manner as soaps but if it released into rivers and lakes it can cause explosive growth of algae.
Thus, it can cause decay of the aquatic ecosystem due to deoxygenation from the decomposition of dead algae. Test tubes with rack 2. Measuring cylinder 3. Beakers 5. Glass rod 6. Hot plate 7. Vacuum filtration apparatus 9. Buchner Funnel Dropper Retort stand and clamp Electronic weightage scale Petri dish 5. Stock soap solution 2. Distilled water 3. Synthetic detergent dynamo 4. Calcium chloride, CaCl2 solution 5. Magnesium chloride, MgCl2 solution 6.
Ferum chloride, FeCl2 solution 7. Tomato sauce 9. The mixture stirred by using stirring rod to mix the contents of the flask. If the mixture should foam to the point of nearly overflowing, the flask removed from the boiling-water bath until the foaming subsides, then continue heated.
The mixture heated for minute or until the alcohol odor is no longer detectable. The filter paper placed inside the Buchner funnel. The filter paper was moisture with water so that it fits flush in the bottom of the funnel 7 The mL of saturated Sodium Chloride, NaCl solution added to the flask to salt out the soap once the flask has cooled.
The mixture from the flask poured into the Buchner funnel. Once all of the liquid has filtered through the funnel, the soap washed with 10 mL of ice-cold water. The suction filtration was continued until the water is removed from the soap. The filter paper and dried soap weighed and the mass to the nearest 0. The mass of the soap by difference was determined and the mass was recorded.
The mixture is stirred until the soap has dissolved and the solution is allowed to cool. When both solutions are cool, the pH of each solution is determined using pH paper.
The solutions, if any, which emulsifies the oil by forming a single layer, is noted. The mixtures are poured into the Waste Container. The three test tubes are cleaned and dried. Each test tube is shaken to mix the solutions. The observations are recorded. Each test tube is shaken to mix the solutions and the solutions are left to stand for three five minutes. The solutions that precipitated are observed.
The test tubes are cleaned and dried. The number of drops of acid added to each mixture is counted. Any precipitate formed in either mixture is observed. Each test tube is shaken to mix the solution. Any emulsification formed in either mixture is observed. Then 20 mL of stock soap solution from part B is placed in the first beaker.
After that, 20 mL of stock detergent solution from Step 2 in Part B is placed in the 2nd beaker. Repeatedly each solution is stirred with a stirrer bar for 5 minutes. Each cloth strip is observed and compared to determine their relative cleanliness. There are three parts of this experiment.
The first part which is Part A is about preparation of the soap. Next, Part B which is about the comparison of soap and detergent properties to test precipitation and emulsifying, followed by Part C, the comparison of cleaning abilities of soap and detergent. In Part A, during the soap preparation, saponification process occur where the fatty acid carboxylate ions are formed in the presence of the strong base which is used sodium hydroxide, NaOH for this experiment.
Then, these carboxylate ions are the conjugate bases of the fatty acids therefore, it is able to accept a proton to form stable compound. In part B, all the comparison of properties had been observed and recorded. The pH value of soap solution and synthetics detergent dynamo is pH 11 and pH 7 respectively.
From the result, the pH value of the soap solution is neutral and synthetic detergent is alkaline solution. Therefore, alkaline detergent is recommended for cleaning because it allowing the cleaner to produce more efficient and effective results than the soap solution. Thus, detergent is better in cleaning compare to the soap solution. This part determined the comparison of oil emulsification for the three types of sample in test tube A, B and C which are distilled water, soap solution and finally the synthetic detergent.
Emulsify means is a colloid of two or more immiscible liquids where one liquid contains a dispersion of the other liquids. From the observation, the distilled water emulsified the oil meanwhile the synthetics detergent and soap solution not emulsified the oil which formed clear solution and cloudy solution respectively. From the result in test tube A, the distilled water emulsified the oil because the mixtures have two immiscible fluids which given time will separate spontaneously.
Under the influence of gravity the oil will rise to the surface and form a layer on top of the water phase. This is what is called gravity separation. Oil is not dissolved in the water phase but is dispersed throughout the water phase as very fine droplets.
It causes the oil to emulsify and separate less readily from the aqueous medium. In test tube B and C, the synthetics detergent and soap solution not emulsified the oil. Detergent and soap solution is attracted to both water and oil. This is reason why detergent and soap not emulsified with oil. Next, the comparison of properties of soap and detergent in hard solution, it represents the water condition in hard water which contains CaCl2, MgCl2 and FeCl2 for each of the test tubes respectively.
By using our soap, precipitate form in three of the test tubes. This is because the metal ions from the hard water will cause the soap to form an insoluble salt. That is why the water does not mix with the soap and forming precipitate. Although soap is a good cleaning agent, its effectiveness is reduced when used in hard water. Hardness in water is caused by the presence of mineral salts because the mineral salts react with soap to form an insoluble precipitate known as soap film or scum.
After that, mineral oil was added to all of the test tubes. Based on the observation, before adding the mineral oil, the precipitate is formed in the soap solution for all three test tubes, but after adding the mineral oil there are no oil emulsified observed in the soap. This is because the hydrocarbon is hydrophobic and soluble with the oil, but micelles will still be form even though the metal ions causing the soap to be insoluble with water.
So that, this is a good characteristics for the soap as the cleaning agent if there no emulsifies oil on the cloth.
Compare to the properties of soap in the hard solution, detergent is more preferable since there is no precipitate and oil emulsified in the detergent solution before and after adding the mineral oil into the detergent solution.
However, although the detergent have the advantages compare to the soap, but there is a significant issue regarding the use of synthetic detergent that is the biodegradability of some of its components. In fact, many of the surfactants initially used in detergents were not biodegradable whereas soaps are biodegradable, apparently can be degraded by bacteria.
The amount of hydrochloric acid need to change the pH of the soap solution to 3 is about 10 drop whereas for detergent solution is about 2 drops. The big difference could be due to the difference in initial value of the pH of the cleaning agents which is 11 for soap solution and 8 for detergent solution.
Therefore, higher concentration of hydronium ion is required to change the soap solution as compared to detergent solution from basic to acidic.
Hard water reduces the cleansing action of the soap as the acid presence in the water convert the soap to an insoluble organic acid. Detergent do not produce precipitate as the pH turned from 8 to 3 since the hydrophobic portion in the detergent differ from soaps in that the nonpolar fatty acids group is replaced with alkyl or aryl sulfonic acid. The sulfonic acid is much stronger than carboxylic acid, thus the detergent do not produces precipitate like soap.
Oil emulsion do not occurred for both sample in hard water since no presence of grease or oil in the sample. However, even if there is grease or mineral oil present in the solution, there will still be no oil emulsion since the hydrophobic portion of the cleaning agents is soluble in nonpolar compound like grease and oil.
In part C, the dirt in the experiment which is tomato sauce contains olive oils along with other organic species Batali are nonpolar species whereas water is polar species. Water alone cannot remove the dirt since oil repels water molecules since it is hydrophobic while water is hydrophilic. Thus, due to dissimilar characteristics, they cannot dissolve in each other. Therefore, they need other medium to allow the removal of dirt from affected area or in this experiment, the cloth strips.
Soap and detergent have both polar and nonpolar region in the molecule which function by breaking down the interface between water and the dirt. They hold the dirt in suspension and allow their removal. Surfactants, Based on the visual comparison between the cloth strips in the three cleaning agents 20mL soap solution, 20mL detergent solution and 20mL detergent , the most clean is the one in the detergent solution, followed by soap solution and detergent without dilution with distilled water.
Thus, showing that detergent solution is the most effective compared to the other two cleaning agents sample. Soap and detergent reduce surface tension in water allowing the water to spread and contacted with the whole cloth strips surface area which then allow the water to encounter the dirt presence on the cloth strips.
They are also emulsifying agents which lead to separation of dirt from the cloth strips. Detergent contained one or more surfactants. The surfactants in detergents can be engineered to perform well under a variety of conditions due to their chemical makeup.
SDAC Thus, making detergent much more effectives compared to soap solution. The cloth strip in the third sample of the cleaning agent which is the detergent without dilution with distilled water shows the least effective cleaning agents since only little amount of dirt is removed.
This could be due to the stirring effect and not even the detergent that functioning as the cleaning agent. Since, the detergent is too concentrated to penetrate the cloth strip and separating the dirt from the cloth strip, it can hardly be concluded that high concentration of detergent without the spreading mechanism which is water molecules is a good way to use the cleaning agent.
Therefore, the right ratio is required between the cleaning agents and water in order for dirt or stains to be removed from the affected area or cloth strips.
0コメント