Why do we use ammonium formate as a hydrogen surrogate instead of using hydrogen gas in this experiment?

Ammonium formate can also be used in palladium on carbon (Pd/C) reduction of functional groups. In the presence of Pd/C, ammonium formate decomposes to hydrogen, carbon dioxide, and ammonia.

Explanation:

This hydrogen gas is adsorbed onto the surface of the palladium metal, where it can react with various functional groups.