Question

Poling process:
(a) reduced $Sn{{O}_{2}}$ to $Sn$
(b) oxidises impurities like iron and removes as scum
(c) uses green poles
(d) involves all of the above

Answer 1

Hint: Polling process is a metallurgical method which employs the process of purification of a certain metal, thereby removing its impurity which is present in the oxide form.

Complete Step by Step Solution:
Let us talk about the Poling process which is a metallurgical process.
● The process employs two stages of refining. The impure metal which is placed in an anode furnace in its molten state is air blown initially to remove sulphur and iron forming iron oxide and sulphur dioxide. Sulphur dioxide is vented off through the off-gas system whereas the iron oxide is skimmed off from top of the copper oxide (or tin oxide in the example of tin). The next step (or the second step) involves a reducing agent used to react with the oxygen in the oxide to form the product metal (copper or tin in the purified form)
● Also, traditionally, green poles were also used as reducing agents. The heat of the metal made the pole emit wood gas which is essentially used to convert the metallic oxide form to the metal.
● Hence, the answer is (d) involves all of the above.

Note: The polling process is primarily employed in the process of purification of oxide contents (impurity) for certain metals such as copper and tin. This is not the most advanced form of purification process. There are possibilities where if the care is not taken, other impurities could in turn get added in the concerned metal.