Which of the following mineral does not contain iron :

Mark the wrong statement

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 _________.

In the electrolysis of alumina to obtain aluminium metal, cryolite is added mainly to

If the impurity in a metal has a greater affinity for oxygen and is more easily oxidised than the metal, then the purification of metal may be carried out by