A compound 'X' on heating with excess conc. Sulphuric acid at 443 K gives an unsaturated compound 'Y' . 'X' also reacts with sodium metal to evolve a colourless gas 'X'. Identify 'X','Y' and 'Z'. Write the equation of th chemical reaction of formation of 'Y' and also write the rule of sulphuric acid in the reaction.