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This extremely useful reaction uses the alkali metal/ammonia solution again to partially reduce aromatic rings.
The term 'homogeneous catalysis' refers to a catalyst that is present in the same medium as the reaction mixture - i.e. in solution.
LiAlH4 is reactive enough to reduce first to aldehyde and then through to alcohol - not able to stop at the aldehyde unless strictly one equivalent is added at low temperature (-780C).
Probably the most common type of reagent used for reductions in organic chemistry is the hydride reagent - i.e. one which reacts as 'H-' - a hydride nucleophile.