http://www.goiit.com/posts/list/organic-chemistry-what-is-lindlar-s-reagent-995836.htm

 lindlars catalyst is palladised charcoal partially deactivated with some poisonous sulphur compounds(like sulphur or quinoline).

It is used to hydrogenate Alkynes to form cis-Alkenes

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A weakened palladium catalyst called Lindlar's catalyst (Pd with CaCO3 and Pb(OAc)2 is very popular . With a weaker catalyst or much milder conditions, it is possible to reduce an alkene without reducing a carbonyl in the same molecule, even if they are conjugated !!!!