Question

Assertion (A): Sulphide ores are concentrated by froth floatation process.

Reason (R): Pine oil acts as a frothing agent in froth floatation process.

Options

• If both A and R are true, and R is the correct explanation of A.

• If both A and R are true, but R is not the correct explanation of A.

• If A is true, but R is false.

• If both A and R are false.

Answer 1

If both A and R are true, but R is not the correct explanation of A.

Explanation:

The assertion is true because froth flotation is the standard method used to concentrate sulphide ores based on the differential wetting properties of the ore and impurities. The reason is also true because pine oil is added to create and sustain the foam that carries mineral particles to the surface. However, R is not the correct explanation for A because the fundamental reason sulphide ores are specifically chosen for this process is that the sulphide particles are hydrophobic and preferentially wetted by oil, while the rocky gangue impurities are hydrophilic and wetted by water.