Total number of  acyclic isomers possible with the formula, C4H6 is ‘X’. Total number of acyclic stereo isomers possible with the formula, C4H6 is ‘Y’. Difference between X and Y is

Number of alkynes = 2 ;Number of terminal alkynes = 1 ;Number of non terminal (internal) alkynes = 1 ;Number of alkadienes = 2 ;Number of cumulative dienes = 1 ;Number of conjugated dienes = 1 ;Number of acyclic isomers = 4 ;Number of cycloalkenes = 4 ;Number of cyclic isomers = 4 ;Number of acyclic structural isomers = 4 ;Number of acyclic stereo isomers = 0 ;Number of cyclic structural isomers = 4 ;Number of cyclic stereo isomers = 0 ;Total number of  structural isomers = 8 ;Total number of  stereo isomers = 0 ;Total number of isomers = 8 ;