2-butyne is treated with H2 /Lindlar's catalyst to give compound X (cis -2-butene) and 2-butyne is treated with Na/ liq. NH3 to produce trans-2-butene (Y) as major product. Note Lindlar's catalyst is H2∕Pd∕CaCO3 which is used for hydrogenation of alkyne to form cis-alkene.