(a) In common practice silver is recovered from silver nitrate solution by the use of copper metal. Name the type of reaction that takes place in this process and give the chemical equation of the reaction involved.

(b) Name the method used for refining silver.

(a) The type of reaction is a displacement reaction. Copper, being more reactive than silver (copper lies above silver in the reactivity series: ... Cu, Hg, Ag, Au), displaces silver from silver nitrate solution.

$$\text{Cu}(s) + 2\text{AgNO}_3(aq) \rightarrow \text{Cu(NO}_3)_2(aq) + 2\text{Ag}(s)$$

Metallic silver is deposited and can be recovered, while copper goes into solution as copper nitrate.

(b) The method used for refining silver (like most impure metals such as copper, zinc, tin, nickel, gold) is electrolytic refining, as described in Section 3.4.6. In this process, a block of impure silver is made the anode and a thin strip of pure silver is made the cathode, with a solution of a silver salt used as the electrolyte. On passing current, pure silver from the anode dissolves into the electrolyte and an equivalent amount of pure silver is deposited on the cathode; soluble impurities go into solution while insoluble impurities settle at the bottom of the anode as anode mud.