A Simple Separation of Cobalt and Nickel Salts

250-mL separating funnel, stand with ring and boss, 100-mL measuring cyclin-der, two 25-mL measuring cylinders, two 250-mL beakers, safety glasses, protective gloves. 

C0CI2 6 H2O, NiCb 6 H2O, 2-butanone, KSCN, distilled water. Experimental Procedure 

25 mL of a 1 % solution of C0CI2 and of a 4 % solution of NiCb are placed in the separating funnel. The almost grey solution is treated with 100 mL of 2-butanone, followed by about 0.6-0.7 g of KSCN. After brief shaking two phases separate the upper one is deep blue, the lower one lime green. 

The aqua complex of the nickel(II) ion retains its green color and its octahedral structure in aqueous solution even in the presence of the SCN ions from the KSCN, which compete with the Cl ions however, these SCN ions displace 

The mixture is shaken for a few minutes with milk of lime (pH 8). The precipitate is separated off and transferred to the container used for collecting less toxic inorganic salts, while the supernatant liquid is poured down the drain. 

---