Activity 4.8

Activity . Take mL ethanol (absolute alcohol) and mL glacial acetic acid along with a few drops of concentrated sulphuric acid in a test tube. Warm in a water-bath for at least five minutes as shown in Fig. . . Pour into a beaker containing - mL of water and smell the resulting mixture. Reactions of ethanoic acid: Reactions of ethanoic acid: Reactions of ethanoic acid: Reactions of ethanoic acid: Reactions of ethanoic acid: (i) Esterification reaction: Esters are most commonly formed by reaction of an acid and an alcohol. Ethanoic acid reacts with absolute ethanol in the presence of an acid catalyst to give an ester – CH COOH CH CH OH CH C C CH CH H O Acid O (E − + − − − − − + thanoic acid) (Ethanol) (Ester) O Generally, esters are sweet-smelling substances. These are used in making perfumes and as flavouring agents. On treating with sodium hydroxide, which is an alkali, the ester is converted back to alcohol and sodium salt of carboxylic acid. This reaction is known as saponification because it is used in the preparation of soap. Soaps are sodium or potassium salts of long chain carboxylic acid. Figure . Figure . Figure . Figure . Figure . Formation of ester Alcohol as a fuel Alcohol as a fuel Alcohol as a fuel Alcohol as a fuel Alcohol as a fuel Sugarcane plants are one of the most efficient convertors of sunlight into chemical energy. Sugarcane juice can be used to prepare molasses which is fermented to give alcohol (ethanol). Some countries now use alcohol as an additive in petrol since it is a cleaner fuel which gives rise to only carbon dioxide and water on burning in sufficient air (oxygen).