Solution

Cupellation is a refining process in metallurgy, where ores or alloyed metals are treated under very high temperatures and have controlled operations to separate noble metals, i.e; gold and silver, from the base metals like lead copper, zinc, antimony bismuth which are present in the ore, The impurities are oxidised and the volatile oxides. This produce escape with the blast of air. Pb present in silver is removed by cupellation process.

Ag(s)+2pb(s)+O2(g)→2Pb0(Ag⁡(s)+2pb(s)+O2(g)→2Pb⁡0(