(a) Name an alcohol and a carboxylic acid having two carbon atoms in their structures. Draw their structures and state how this alcohol can be converted into a carboxylic acid. What happens when these two compounds react in the presence of an acid? Write chemical equations for the reactions involved in the two cases mentioned above. OR (b) What are soaps? Write the structure of a soap molecule. Explain the cleansing action of a soap. Why are soaps not considered suitable for washing clothes in a region where water is hard? How is this problem overcomed?

(a) An alcohol with two carbon atoms in its structure is ethanol (C2H5OH). A carboxylic acid with two carbon atoms in its structure is acetic acid (CH3COOH). The structure of ethanol is: $CH_3CH_2OH$ The structure of acetic acid is: $CH_3COOH$ Ethanol can be converted into acetic acid by oxidation: $CH_3CH_2OH + 2O \rightarrow CH_3COOH + H_2O$ When ethanol and acetic acid react in the presence of an acid, they form ethyl acetate: $CH_3CH_2OH + CH_3COOH \rightarrow CH_3COOCH_2CH_3 + H_2O$ OR (b) Soaps are the sodium and potassium salts of higher fatty acids. The structure of a soap molecule is: $R-COO^-Na^+$ Where R is the hydrocarbon chain of the fatty acid. The cleansing action of a soap is due to its ability to emulsify oils and fats. Soaps are not considered suitable for washing clothes in a region where water is hard because the calcium and magnesium ions in hard water react with the soap to form an insoluble substance called soap scum. This problem can be overcome by using a water softener or a detergent that is specifically designed to work in hard water.