Hydrogenation of pyridine compared to other heteroaromatic rings Why does pyridine require the lowest temperature for hydrogenation, even though it has it has the highest resonance energy amongst pyridine, pyrrole and furan? Is it just because of the increase in the absolute pressure or does the HCl also effect the reaction somehow?
When we reduce pyridine using the $\ce{H2/Pt/HCl}$ reagent-catalyst combination, we require a significantly lower temperature and pressure compared to other similar reductions (but without $\ce{HCl}$), because $\ce{H+}$ (and other Lewis acids for that matter) will go and add to the nitrogen atom, forming pyridinium salts.

This makes the compound more reactive towards reduction (as a partial positive charge will develop in the ring).