Selective hydrogenation

A method for the treatment of a gaseous mixture comprising ethylene and acetylene, which method comprises selectively hydrogenating the acetylene therein by contacting said mixture together with hydrogen with a catalyst consisting essentially of particles of alpha alumina containing metallic components consisting essentially of palladium and silver wherein the palladium is about 0.01 to about 0.025 weight percent of the catalyst, the weight percent silver is at least twice that of the palladium, the silver is distributed throughout said catalyst particles, and substantially all of the palladium is concentrated in an area within 300 microns of the exterior surface of at least 90 percent of the catalyst particles.