Given below are two statements:
Statement I : Sphalerite is a sulphide ore of zinc and copper glance is a sulphide ore of copper.
Statement II : It is possible to separate two sulphide ores by adjusting proportion of oil to water or by using depressants in a froth flotation method.
Choose the most appropriate answer from the options given below:

We first examine Statement I. Sphalerite is another name for zinc blende, whose chemical formula is $$\text{ZnS}$$. Because the anion is $$\text{S}^{2-}$$, zinc blende is unambiguously a sulphide ore. It supplies the metal zinc, and it contains no copper. Copper glance, on the other hand, has the formula $$\text{Cu}_2\text{S}$$; the suffix “glance” is traditionally used for certain sulphide minerals. Again, the anion present is $$\text{S}^{2-}$$, so copper glance is a sulphide ore which yields copper. Thus both parts of Statement I agree with standard mineralogy. So Statement I is true.

Now we analyse Statement II. The froth-flotation process is based on the principle that different sulphide particles can be rendered either hydrophobic or hydrophilic by suitable reagents. The general rule used in froth flotation is stated as follows:

“If oil-water proportion or specific depressants/activators are adjusted appropriately, then even two sulphide ores present in the same mixture can be separated because only the hydrophobic particles preferentially attach to air bubbles and rise in the froth.”

For example, in an ore containing $$\text{PbS}$$ (galena) and $$\text{ZnS}$$ (sphalerite), sodium cyanide $$(\text{NaCN})$$ is employed as a depressant for $$\text{ZnS}$$. The cyanide forms a complex with zinc, $$\text{[Zn(CN)}_4]^{2-}$$, making the zinc compound hydrophilic, while $$\text{PbS}$$ remains hydrophobic and floats. By merely varying the proportion of oil to water or by adding a depressant such as $$\text{NaCN}$$, we successfully separate the two sulphide minerals. This practical example directly verifies the claim made in Statement II. Therefore Statement II is also true.

Since we have found Statement I to be true and Statement II to be true, the option that matches this situation is “Both Statement I and Statement II are true,” which is Option B in the list provided.

Hence, the correct answer is Option B.