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

The byproduct in the extraction of iron is

The Ellingham diagram for zinc,magnesium,and carbon converting into corresponding oxides is shown below. To make the following reduction process spontaneous,the temperature should be:
$ZnO + C \to Zn + CO$

Which statement is correct regarding the slag formed during the extraction of copper or iron?

Extraction of gold $(Au)$ involves the formation of complex ions $X$ and $Y$ as shown in the reaction: $\text{Gold ore}$ $\xrightarrow{CN^-, H_2O, O_2} HO^- + X$ $\xrightarrow{Zn} Y + Au$. $X$ and $Y$ respectively are:

Which one of the following electrolytes is used in Down's process for the extraction of sodium metal?