Question

Poling process is used _______.
(A) for the removal of $C{{u}_{2}}O$ from $Cu$
(B) for the removal of $A{{l}_{2}}{{O}_{3}}$ from $Al$
(C) for the removal of $F{{e}_{2}}{{O}_{3}}$ from $Fe$
(D) All of these

Answer 1

Hint: Poling is a process in which the copper metal is refined. It is based on reducing the metal from a higher oxidation state.

Complete answer:
As we know, that extraction of pure metals from their ores is a long and tedious process. It involves many steps and requires both man and machines for keeping up with supply and demand. Ores are where the metals are found in earth’s crust. But here, they are mixed with other elements which are often treated as impurities.
To ensure that all the impurities are eliminated, complex processes are used. Poling is one such process. It is actually a refining process for copper and also tin, when they are present in their oxide forms. As it is only for specific metals, it is necessary to remove all others that are unwanted. So before poling is initiated, a purification process is carried out for removing metals which are not copper or tin.
The metals are changed into their molten state and air is blown gently through the mixture. The air oxidises both impurities such as metals like iron and non-metals like sulphur and also copper into their oxide forms. Iron oxide is skimmed off or sometimes decanted slowly and the non-metals escape to outside in their gaseous forms leaving only the desired metals in the mixture.
After this purification, the actual poling process starts. In an anode furnace, copper oxide is reduced to metallic copper by the action of reducing agents such as natural gas, diesel, ammonia etc. and in this way we obtain the pure metal.
In the traditional poling method, freshly cut branches of green trees were used as poles in the reaction mixture. The heat from the molten metals triggered these poles to release reagents that reduce metal oxides into pure metals. So, now you know how this process got its name.
So, the correct answer is “Option A”.

Note: Unlike the traditional way, Polling today is done in a very regulated manner. The reducing agents used are specific to the metals the manufacturers want to reduce.
Tin is also reduced in the same way as copper. Therefore, polling is used for both tin and copper.