(a) Name the reaction which is usually used in the conversion of vegetable oils to fats. Explain the reaction involved in detail. Write a chemical equation to illustrate your answer.
(b) What is saponification? Write the chemical equation of the reaction involved in this process. Name all the substances which take part in this process and also those which are formed.
(c) Why does micelle formation take place when soap is added to water? Will a micelle be formed in other solvents like ethanol also?
(a) Catalytic hydrogenation is usually in conversion of vegetable oils fats.
Hydrogenation of oils: Vegetables oils are unsaturated fats having double bonds between some of their carbon atoms and can undergo addition reactions. When a vegetable oil (like groundnut oil) is heated with hydrogen in the presence of finely divided nickel as catalyst, then a saturated fat called vegetable ghee (or vanaspati ghee) is formed. This reaction is called hydrogenation of oils and it can be represented as follows:
(b) The process of making soap by the hydrolysis of facts and oils with alkalis is called saponification.
Fat or Oil + Sodium hydroxide + Heat → Soap + Glycerol
(c) Soap are sodium or potassium salts of long-chain carboxylic acids. When soap is added to the water, the hydrophilic end (acid end) will align along the surface of water and the hydrophobic tail(carbon chain) remain out of water.
When a soap is dissolved in water, it forms a colloidal suspension in water in which the soap molecules cluster together to form spherical aggregates called micelles. In a soap micelle, soap molecules are arranged radially with hydrocarbon ends directed towards the centre and ionic ends directed outwards.
No, micelle will not be formed in other solvents such as ethanol because hydrocarbon chains of soap molecules are soluble in organic solvents like ethanol.