Question

In a mixture of PbS, ZnS, and $Fe{{S}_{2}}$, each component is separated from the other by using the reagents in which of the following sequence in the froth floatation process?
(a)- Potassium ethyl xanthate, KCN, NaOH, copper sulfate, acid
(b)- KCN, $CuS{{O}_{4}}$, acid
(c)- Potassium ethyl xanthate, KCN
(d)- None of these

Answer 1

Hint: Froth floatation is a process that is involved in the extraction of metal from its ore, and this is used for the concentration or benefaction of the ore. Most sulfide ores are concentrated by this process. In this process, collectors, stabilizers, and depressants are added.

Complete answer:
We metal from nature, but in nature, they are not found as such because they are combined with other elements, i.e., they are found in ores. These ores of the specific metals undergo many step-by-step processes for the extraction of metal.
Froth floatation is a process that is involved in the extraction of metal from its ore, and this is used for the concentration or benefaction of the ore. Most sulfide ores are concentrated by this process.
The main principle of this process is that the surface of the sulfide ores is preferentially wetted by oil while the surfaces of the gauge particles are preferentially wetted by water.
First, the ore is crushed into a fine powder, mixed in water to form a suspension in the tank, and collectors and froth stabilizers are added. Then this suspension is agitated so that froth can be formed.
Collector like Potassium ethyl xanthate is added to the galena (PbS) along with KCN and NaOH or alkali which are depressants because it depresses the property of ZnS and $Fe{{S}_{2}}$. Now, $CuS{{O}_{4}}$ which is an activator is added which is used to separate ZnS, and then the acid is added for the separation of $Fe{{S}_{2}}$.

Therefore, the correct answer is an option (a).

Note:
Some other examples of collectors are pine oil, ethyl xanthates, etc. examples of froth stabilizers are cresol and aniline. Depressants are mainly used, so that more than one type of compound would not get mixed into the froth.