Copper matte contains

In the Goldschmidt thermite process,which substance acts as the reducing agent?

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

Which of the following metals is extracted by the electrolytic reduction method?

The value of ${\Delta _r}{G^\Theta }$ for the formation of $Cr_2O_3$ is $-540 \, kJ \, mol^{-1}$ and that of $Al_2O_3$ is $-827 \, kJ \, mol^{-1}$. Is the reduction of $Cr_2O_3$ possible with $Al$?

In the electrolytic extraction of aluminium,cryolite is used: