Question

Elements like \[Pb\] and \[Sn\] can be extracted from their chief ore by:
A. carbon reduction and self-reduction respectively
B. self-reduction and carbon reduction separately
C. electrolysis and self-reduction respectively
D. self-reduction and electrolysis respectively

Answer 1

Hint: We are given the metals and we have to find their extraction process from their ore. There are many ways through which metal can be obtained from their ores. Some of them are self, reduction and electrolysis of the ore. It depends on the nature of metal how it can be extracted from ore.

Complete answer:
We may define ore as a naturally occurring substance from which we can extract the metal at an economical rate. The way of extraction of metal from its ore depends on the physical properties of the metal. Generally lead exists in the form of sulphides or oxide. The sulphide ore of the lead is known as galena \[\left( {PbS} \right)\]. It can be obtained by the process of self-reduction. This can be depicted as,
\[2PbS{\text{ + 3}}{{\text{O}}_2}{\text{ }}\xrightarrow{{}}{\text{ 2PbO + 2 S}}{{\text{O}}_2}\]
\[PbS{\text{ + 2PbO }}\xrightarrow{{}}{\text{ 3Pb + S}}{{\text{O}}_2}\]
Thus lead is formed as a result of self-reduction. This process is also known as roasting. Here complete oxygen is provided. Whereas \[Sn\] can be obtained by carbon reduction techniques. Here we add carbon to the oxide ore of \[Sn\] , thus giving the metal. This can be depicted as,
\[Sn{O_2}{\text{ + C }}\xrightarrow{{}}{\text{ Sn + CO}}\]
\[Sn{O_2}{\text{ + 2CO }}\xrightarrow{{}}{\text{ Sn + 2C}}{{\text{O}}_2}\]
Thus the metal can be obtained by using a carbon reduction process. Hence the correct option is B. self-reduction and carbon reduction separately.

Note:
We can extract the metals from their ores in various ways. Sulphide ores always undergo a self-reduction process. While in case of \[Sn\] we use coke as a reducing agent which reduces its ore and hence we get the metal. It is reduced by carbon reduction techniques. In roasting we provide a sufficient amount of oxygen during the reaction.