Which of the following is the correct chemical formula for slag?

The reaction for obtaining the metal $(M)$ from its oxide $(M_{2}O_{3})$ ore is given by
$M_{2}O_{3(s)} + 2 Al(\ell) \xrightarrow{\text{Heat}} Al_{2}O_{3}(\ell) + 2 M_{(s)}$, $(s = \text{solid}, \ell = \text{liquid})$
In this case, $M$ is

Which of the following statements is incorrect regarding the electrolysis of $Al_2O_3$ by the Hall-Heroult process?

Explain the role of thermodynamics in the extraction of elements. Or,explain how thermodynamics is helpful in the selection of a reducing agent for metallurgical operations.

Iron is extracted from magnetite by reduction with

In the equation,$4M + 8CN^{-} + 2H_2O + O_2 \to 4[M(CN)_2]^- + 4OH^{-}$,the metal $M$ is