An organic compound X of molecular formula C₂H₄O₂ gives brisk effervescence with sodium hydrogencarbonate. Give the name and formula of X.

43 What happens when vegetable oils are hydrogenated? Name the catalyst used. 43 What is the advantage of detergents over soaps for washing clothes? Also state One disadvantage. 44 A mixture of ethyne (acetylene) and oxygen is burnt for welding. Can you tell why a mixture of ethyne and air is not used? 44 Name a chemical reaction which is characteristic of unsaturated hydrocarbons (like alkenes and alkynes).