In the alumino-thermite process,$Al$ acts as

$FeCr_2O_4$ (chromite) is converted to $Cr$ by following steps:
Chromite $\xrightarrow{I} Na_2CrO_4$ $\xrightarrow{II} Cr_2O_3$ $\xrightarrow{III} Cr$
Reagents in $I, II$ and $III$ steps might be:
$I$ Step $-$ $II$ Step $-$ $III$ Step

The metal extracted by the electrolysis of its fused salt is

Which of the following elements has the lowest tendency to form its oxide?

Flux is used to remove $........$.

The function of fluorspar $(CaF_2)$ in the electrolytic reduction of alumina $(Al_2O_3)$ dissolved in fused cryolite $(Na_3AlF_6)$ is