Thermite is a mixture of iron oxide and which of the following?

Thermite is a mixture of $X$ parts of ferric oxide and $Y$ parts of aluminium powder. $X, Y$ respectively are

To prevent magnesium from oxidation in the electrolytic extraction process,which of the following is done?

Which metal cannot be extracted by the smelting process?

The substance used in the thermite process of reducing metal ores is

In the $Bessemer$ and $open-hearth$ process for the manufacture of steel,which one of the following is used for the removal of carbon in part or whole?
$Bessemer \to$ $Open-hearth$