In activity series, metals are placed in decreasing order of reactivity with most reactive metal at the top and least reactive metal at the bottom. Depending upon the reactivity of metals, different methods are used for their extraction from respective ores.
For example:
1. Extraction by electrolysis: Metals at the top of the activity series are extracted from their ores by electrolysis. Being highly reactive, they cannot be reduced by common reducing agent (C, CO, H2 )
For example: K, Na, Ca, Mg,Al.
2. Extraction by common reducing agents: Metals at the middle of the activity series, being less reactive, can be extracted from their ores by reduction with common reducing agents like C, CO, H2
For example: Zn, Fe, Pb, Cu.
3. Extraction by thermal decomposition: Metals near the bottom of the activity series, due to their very low reactivity, can be extracted from their ores, by heating only.
For example: Hg, Ag.
4. Metal at the bottom of the activity series exist in native state (Au, Pt).
5. State the electrode reaction at the respective electrodes during extraction of Al from Al2 O3
