In the reaction, PCl LiAlH alc.KOH CH COOH A B C -> -> -> the product C is :

4 LiAlH is a strong reducing agent and it will convert carbonyl compounds into alcohol after reduction. When 5 PCl reacts with the obtained product in sequence 1, it will undergo nucleophilic substitution and replace OH by Cl. Then the obtained product is reacted with alcoholic KOH, it will undergo dehydro-halogenation reaction. The reaction is shown below- 5 4 PCl LiAlH 3 3 2 3 2 CH COOH CH CH OH CH CH Cl -> -> alc.KOH 2 2 H C CH -> Thus, the correct option is (b) Ethylene