Which form of iron has the highest melting point?

Impure silver ore $+ CN^{-} + H_2O \xrightarrow{O_2} [X]^{-} + OH^{-}$
$[X]^{-} + Zn \longrightarrow [Y]^{2-} + Ag \text{ (pure)}$
The coordination numbers of the metals in $[X]$ and $[Y]$ are respectively

$Pb$ and $Sn$ are extracted from their chief ores by:

Predict conditions under which $Al$ might be expected to reduce $MgO$.

In the alumino thermite process,$Al$ acts as

In the smelting of roasted copper pyrites ore,melting occurs so that the first reaction is: