Question

how is the structure of alkynes different from that of alkenes

Answer 1

alkynes are triply bonded carbon bonds in a compound having three bonds in three perpendicular planes

alkenes are dounbly bonded carbon bonds in a compound having two bonds (one in the plane and one out of the plane)

Answer 2

alkenes contains double bonded carbon. where as alkyne contains triple bonded carbon .
molecular formula of alkene.. CnH2n
molecular formula of alkyne... CnH2n-2