Question

Assertion (A): $CuFe{{S}_{2}}$ is concentrated by froth floatation method.
Reason (R): $CuFe{{S}_{2}}$ is the main ore of copper.
A. Both assertion and reason are correct and reason is the correct explanation for assertion.
B. Both assertion and reason are correct but reason is not the correct explanation for assertion.
C. Assertion is correct but reason is incorrect.
D. Assertion is incorrect and reason is correct.

Answer 1

To answer this question, first of all try to recall what the froth floatation process entails and in which cases it is chosen as a method of concentration. Generally, sulphide ores are usually concentrated by this process.

Complete step by step answer:
We should know that in ore or mineral concentration, froth floatation is a method by which commercially important minerals are separated from their impurities and other minerals by collecting them on the top surface of a froth layer.
During the process, the ores are crushed into very fine powder sized particles which are then mixed with water. This step is referred to as the comminution process in which the surface area of the ore is increased. A collector which acts as a surfactant chemical then is added to the slurry. This enhances the hydrophobic nature of the mineral. This slurry is then converted to the pulp and then is added in the container filled with water and then air jets are forced into it to produce bubbles. The required mineral is repelled by water and thus gets attached to the air bubbles.
Here, $CuFe{{S}_{2}}$ is copper pyrite which is considered as one of the main ore of copper. It is a copper iron sulphide ore. So, as it is a sulphide ore thus it may be used for the concentration by froth floatation method. But we cannot say that it is concentrated by this process as it is considered as the main ore of copper.
So, the correct answer is “Option B”.

Note: It is important to note that pyrites have a chemical formula $Fe{{S}_{2}}$ and it is an iron sulphide. The basic principle of separation in the process of froth floatation is the difference in the wetting ability of the ore and the remaining impurities.