Question

Liquation method is used for the purification of which of the following metals?
A. Tin
B. Lead
C. Bismuth
D. All of these

Answer 1

Hint: Liquation is used for the refining of metals having low melting point and having impurities of high melting point or vice versa. There must be a difference in the melting point of the constituents.

Complete step by step answer:
Liquation is a metallurgical technique to separate metals from an ore, metal or alloy. This is done by heating the material until one of the constituents starts melting and the other remains solid. The liquid melt is drained away from the other and collected. Earlier, it was used to extract antimony minerals from ore. It is also used to remove lead containing silver from copper. The first use of liquation on an industrial scale was in Germany in the mid-15th century. In the process, impure metal is heated on the sloping hearth of a furnace. If the impurities have a higher melting point than the metal, the pure metal flows down leaving behind the non-fusible material on the hearth. However, the process is not 100% efficient. Some of the metal is lost in slag and some is lost in burning. The metals which have a noticeable difference between the metal and its respective impurities are: Pb, Sn, Sb, Bi and Hg.

Hence, the correct answer is (D) All of these.

Note: A student must either know the refining process used for different metals or must know the impurities present in a metal and their melting points. It is advised to follow the former.