The metal which is extracted by oxidation and subsequent reduction from its ore is :

Solution

Chemistry ma’am · 3 steps

Follow the silver atom: cyanide and air pull it out as Ag(I), then zinc gives it back as metal.

1. Oxidation by leaching. Silver is leached with dilute NaCN in the presence of air. Oxygen oxidises Ag(0) to Ag(I), which dissolves as the complex [Ag(CN)₂]⁻.

   4Ag + 8CN⁻ + O₂ + 2H₂O → 4[Ag(CN)₂]⁻ + 4OH⁻

2. Reduction by zinc. Zinc is more reactive than silver, so it displaces it: 2[Ag(CN)₂]⁻ + Zn → [Zn(CN)₄]²⁻ + 2Ag. Ag(I) is reduced back to the metal.

   Metal	Key extraction step	Metal oxidised first?
   Al	Bayer leaching, then electrolysis of Al₂O₃	No, Al stays +3 until reduced
   Cu	Roasting, then self-reduction of Cu₂S with Cu₂O	No, sulfur is oxidised, Cu stays +1
   Ag	Cyanide leaching with O₂, then Zn	Yes, Ag(0) to Ag(I), then back to Ag(0)
   Fe	Reduction of Fe₂O₃ by CO in a blast furnace	No, only reduction

3. So. Only silver goes through an oxidation step and then a reduction step, so the answer is (c) Ag.

The idea to keep. Silver and gold are leached with CN⁻ and air, which oxidises them into soluble cyano complexes. Zinc then reduces them back to the metal. That is oxidation followed by reduction.

Answer from the NTA final answer key. Solution by PrepWiser.