Question

The auto reduction process is not used in the metallurgy of:
A. $Hg$
B. $Cu$
C. $Pb$
D. $Fe$

Answer 1

Hint: Metallurgy is defined as the process which is used to extract metals in its pure form. The auto reduction process is used for the extraction of pure metals from their ores. Ore is the naturally occurring form of metal. It contains impurities which are removed by certain processes.

Complete answer:
The auto reduction is the process in which sulphide ores of less electropositive metals are heated in air to convert that some part of ore into oxide or sulphate which the reacts with remaining sulphide ore in absence of air which gives pure metal and sulphur dioxide. In this process, less electronegative metals are extracted. Electronegativity is the tendency of a metal to attract a shared pair of electrons. Among given options $Hg$, $Cu$ and $Pb$ are less electronegative elements. So for extraction of these metals the auto reduction process is used. In this question, we have to find which metal is not extracted by this process.

So the answer to this question is option D that is $Fe$.

Additional information:
Metallurgy is a series of processes to get pure metal from different ores. This process involves various steps to be followed which are given below
1. Getting an ore from natural resources by various methods such as mining.
2. Crushing and grinding of that ore.
3. The concentration of ore by various methods such as gravity separation, magnetic separation, leaching, froth floatation.
4. Roasting and calcination (depending on the requirement)
5. Reduction (Reduction by carbon, electrolysis, heat alone, carbon monoxide)
6. Refining by appropriate method some methods are given such as distillation, liquefaction, oxidation and electrorefining.
After all these processes are done according to the ore or properties of elements we get a pure metal extracted from its ore.

Note:
Froth floatation process is a process used for separating hydrophobic materials from hydrophilic materials. This process is used in mineral processing, paper recycling and wastewater treatment.