Complete reduction to the alkane occurs when palladium on carbon(Pd/C) is useed as catalyst, but hydrogenation can be stopped at the alkene
if the less active Lindlar catalyst is used. (the Lindlar catalyst is a finely divided palladium metal that has been precipitated onto a calcium carbonate support and then deactivated by treatment with lead acetate and quinoline, an aromatic amine.) The hydrogenation occurs with syn stereochemistry, giving a cis alkene product.