Blister copper is refined by stirring molten impure metal with green logs of wood because such a wood liberates hydrocarbon gases (like $CH_4$) . This process $X$ is called . . . . . . . . . and the metal contains impurities of $Y$ is …….. .

Thermite is a mixture of

Railway wagon axles are made by heating iron rods embedded in charcoal powder. This process is known as:

When aqueous solution of cupric bromide is electrolyzed, the product obtained at cathode will be 

Which of the following does not contain $Mg$ :