Palladium: Palladium-Gold Fused with Silver, Parted in Nitric Acid, Thrown Down by Zinc (Roscoe 1913)

Gold resists nitric acid; palladium and silver do not. Diluting the alloy with silver lets the acid reach the palladium; salt then takes out the silver and zinc throws down the palladium. Result: palladium, a silver-white metal that melts at 1549 °C, lowest of the platinum metals. The gold stays behind undissolved. Source: Roscoe and Schorlemmer, A Treatise on Chemistry vol. 2 (1913), pp. 1336-1337. Not given: amounts and temperatures. Picture drawn by Youblob.