In the Mond Process, Nickel Is Purified by

In the Mond process, nickel is purified by

A) dissolving the crude ore in sulfuric acid, and precipitating the nickel(II) ion as the sulfate salt.
B) dissolving the crude ore in a lye (NaOH) solution, and precipitating the nickel(II) ion as the hydroxide salt.
C) heating the crude ore to its melting point and electrolytically reducing the nickel(II) ions to form the metal.
D) passing sodium gas over the crude ore at high temperatures, chemically reducing the nickel(II) to nickel metal.
E) passing carbon monoxide over the impure metal at high temperature, forming the volatile Ni(CO) ₄ which is removed as a gas.