Which of the following is slag?

Explain the leaching and oxidation-reduction process in the metallurgy of gold.

The function of fluorspar $(CaF_2)$ in the electrolytic reduction of alumina $(Al_2O_3)$ dissolved in fused cryolite $(Na_3AlF_6)$ is

$Al_{2}O_{3}$ was leached with alkali to get $X$. The solution of $X$ on passing of gas $Y$,forms $Z$. $X$,$Y$ and $Z$ respectively are

The $CORRECT$ match is:
Ores - Common extraction method

Extraction of a metal $(M)$ from its sulfide ore $(M_2S)$ involves the following chemical reactions:
$2M_2S + 3O_2 \xrightarrow{\text{heat}} 2M_2O + 2SO_2 \uparrow$
$M_2S + 2M_2O \xrightarrow{\text{heat}} 6M + SO_2 \uparrow$
The metal $(M)$ may be