In this experiment a triglyceride will be hydrolyzed in order to lớn prepare glycerol plus the salt of the corresponding fatty acids (soap).

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Soap is produced by the saponification (hydrolysis) of a triglyceride (fat or oil). (See Figure 1.) In this process the triglyceride is reacted with a strong base such as sodium or potassium hydroxide lớn produce glycerol & fatty acid salts. The salt of the fatty acid is called a soap. Fatty acids are straight-chain monocarboxylic acids. The most common fatty acids range in form size from 10-20 carbons & most often have an even number of carbon atoms including the carboxyl group carbon. The carbon-carbon bonds in saturated fatty acids are all single bonds, while unsaturated fatty acids have one or more carbon-carbon double bonds in their chains. One example of a saturated fatty acid is palmitic acid, CH3—(CH2)14—CO2H. Fatty acids are seldom found as không lấy phí molecules in nature but are most often a part of a larger molecule called a triglyceride. Triglycerides consist of a three-membered carbon chain (glycerol backbone) with a fatty acid bonded to each of the three carbon atoms in the glycerol backbone. The bond between the fatty acid & the glycerol backbone is referred khổng lồ as an ester linkage. In the saponification process, the ester linkage is broken to size glycerol and soap.

The saponification process is a hydrolysis reaction, which is the reversal of the esterification reaction. In this experiment, we will use a saturated fat made from hydrogenated olive oil (glycerol tristearate) to lớn prepare a soap, which will be primarily sodium stearate.


Complete the pre-lab assignment in briz15.com.


Place 0.18 g of glycerol tristearate in a 5 mL conical vial. Showroom 1.5 mL of a 50:50 water:ethanol solution that contains 0.18 g. Of sodium hydroxide. Add an air condenser & gently reflux the mixture by heating it on a hot plate equipped with an aluminum heating block for 30 minutes. Monitor the temperature closely khổng lồ avoid the evaporation of the ethanol. At the end of the reaction period, some of the soap will have precipitated. Transfer the mixture lớn a small Erlenmeyer flask containing a solution of 0.8 g of sodium chloride in 3 mL of water. Collect the precipitated soap on a Hirsch funnel và wash it không tính tiền of excess sodium hydroxide & salt using 4 mL of ice water. Thử nghiệm the soap by adding a very small piece lớn a kiểm tra tube with 4 mL of water. Cap the tube and shake it. Cảnh báo the kích cỡ and stability of the bubbles. địa chỉ cửa hàng a crystal of magnesium chloride to the tube và shake again. Cảnh báo any differences. Repeat the same tests with a few grains of commercial laundry detergent and record your results in the lab worksheet.

In-Lab Questions

Download and print the following worksheet. You will use this worksheet to record your answers khổng lồ the In-Lab questions.

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Record the following data.
Question 3: Theoretical Yield of sodium stearate__________________ mol,__________________ gQuestion 4: Percentage Yield__________________
Question 6: Observations:Soap in plain water ________________________________________Soap in plain water plus magnesium chloride _________________________________Detergent in plain water___________________________________Detergent in plain water plus magnesium chloride_____________________________