The choice of a reducing agent in a particular case depends on thermodynamic factors. How far do you agree with this statement? Support your opinion with two examples.

Aluminium is extracted from alumina $(Al_2O_3)$ by electrolysis of a molten mixture of

Consider the following reactions of metallurgy:
Ore '$X$' $\xrightarrow{\text{Roasting}}$ '$Y$' + $SO_2$ $\uparrow$
Ore '$Z$' $\xrightarrow{\text{Calcination}}$ '$Y$' + $CO_2$ $\uparrow$
'$Y$' + $C$ $\xrightarrow{1673 \ K}$ '$A$' (vapour) + '$B$' $(g)$
where '$A$' and '$B$' are respectively:

Carbon reduction is not used to obtain $Cr$ and $Mn$ because

Consider the following reactions at $1000\,^{\circ}C$:
$(I)$ $Zn_{(s)} + 1/2 O_{2(g)} \xrightarrow{\Delta} ZnO_{(s)};$ $\Delta G^o = -360\,kJ\,mol^{-1}$
$(II)$ $C_{(s)} + 1/2 O_{2(g)} \xrightarrow{\Delta} CO_{(g)};$ $\Delta G^o = -460\,kJ\,mol^{-1}$
Choose the correct statement at $1000\,^{\circ}C$.

Copper is the most noble of the first row transition metals and occurs in small deposits in several countries. Ores of copper include chalcanthite $(CuSO_4 \cdot 5H_2O)$,atacamite $(Cu_2Cl(OH)_3)$,cuprite $(Cu_2O)$,copper glance $(Cu_2S)$ and malachite $(Cu_2(OH)_2CO_3)$. However,$80\%$ of the world copper production comes from the ore of chalcopyrite $(CuFeS_2)$. The extraction of copper from chalcopyrite involves partial roasting,removal of iron and self-reduction. $1.$ Partial roasting of chalcopyrite produces: $(A)$ $Cu_2S$ and $FeO$ $(B)$ $Cu_2O$ and $FeO$ $(C)$ $CuS$ and $Fe_2O_3$ $(D)$ $Cu_2O$ and $Fe_2O_3$. $2.$ Iron is removed from chalcopyrite as: $(A)$ $FeO$ $(B)$ $FeS$ $(C)$ $Fe_2O_3$ $(D)$ $FeSiO_3$. $3.$ In self-reduction,the reducing species is: $(A)$ $S$ $(B)$ $O^{2-}$ $(C)$ $S^{2-}$ $(D)$ $SO_2$. Give the answer for questions $1, 2$ and $3$.