Over the last few years we have investigated the hydrogenation of higher molecular weight alkynes. Our studies have led us to re-assess the classical theories describing these types of system and to develop new concepts to allow us to interpret the data. In general, the extension of kinetic and mechanistic understanding from the knowledge base developed from ethyne hydrogenation is invalid. Indeed a better description would be that ethyne is a special case. We have investigated not only the primary hydrogenation but also the hydrogenation of the alkene and have examined in detail competitive reactions between alkynes, and alkynes and alkenes. We have been able to show the presence of multiple adsorption sites of varying reactivity, that the hydrogen transfer mechanism can be affected by co-absorbed, but unreactive, species, that the kinetic rate description is variable and depends on conversion, and that the alkyne hydrogenation reaction is structure sensitive.