In the extraction process of copper, the product obtained after carrying out the reactions

(i) $$2 \mathrm{Cu}_{2} \mathrm{~S}+3 \mathrm{O}_{2} \rightarrow 2 \mathrm{Cu}_{2} \mathrm{O}+2 \mathrm{SO}_{2}$$

(ii) $$2 \mathrm{Cu}_{2} \mathrm{O}+\mathrm{Cu}_{2} \mathrm{~S} \rightarrow 6 \mathrm{Cu}+\mathrm{SO}_{2}$$ is called

Gibbs energy vs T plot for the formation of oxides is given below.

For the given diagram, the correct statement is -

Which of the following is used as a stabilizer during the concentration of sulphide ores?

In Hall - Heroult process, the following is used for reducing $$\mathrm{Al}_{2} \mathrm{O}_{3}$$ :-