Identify the substances Q, R, and S, name the ore, and explain the necessity of concentrating the ore.

a)

i) Gas Q: Zinc vapor ($\text{Zn(g)}$)

ii) Liquid R: Sulfuric acid ($\text{H}_2\text{SO}_4$)

iii) Residues S: Insoluble impurities (gangue) and unreacted ore.

b) The sulphide ore used is zinc blende (or sphalerite, $\text{ZnS}$).

c)

i) It is necessary to concentrate the ore to remove unwanted gangue (impurities) and increase the percentage of zinc in the ore. This makes the subsequent extraction processes more economical and efficient by reducing the volume of material to be processed.

ii) The process of concentrating the ore