he method of extraction of crude metal from concentrated ore involves the reduction. Among the following the incorrect method for the given metal isCarbon reduction method is used for Cu, Fe and zinc with the thermodynamic feasibility in the order of Zn < Fe < CuThe Hall-Heroult process of electrolysis involves overall reaction,2Al2O3 + 3C → 4 Al + 3CO2Low grade copper ores are reduced by scrap zinc or H2The extraction of gold and silver by displacement method involves zinc as reducing agent

The statement "Carbon reduction method is used for Cu, Fe and zinc with the thermodynamic feasibility in the order of Zn < Fe < Cu" is incorrect. The carbon reduction method is not typically used for copper (Cu). Copper is usually extracted using the method of pyrometallurgy, which involves high temperature treatments such as smelting and refining. The carbon reduction method is more commonly used for iron (Fe) and zinc (Zn), but not copper.

The Hall-Heroult process is correctly described. It is an electrolytic process used to extract aluminium from its ore, bauxite. The overall reaction is indeed 2Al2O3 + 3C → 4 Al + 3CO2.

The statement "Low grade copper ores are reduced by scrap zinc or H2" is also incorrect. Low grade copper ores are typically processed using hydrometallurgical methods, such as heap leaching, solvent extraction, and electrowinning (SX-EW), not by reduction with scrap zinc or hydrogen.

The extraction of gold and silver by the displacement method does indeed involve zinc as the reducing agent. This is known as the Parkes process, where zinc is added to lead that contains silver and gold. The zinc reacts with the silver and gold to form a zinc-silver-gold alloy, which can be separated from the lead.