For the electrolytic production of aluminium,$(i)$ the cathode and $(ii)$ the anode are made of

In the alumino-thermite process,the ignition mixture is a mixture of ..........

Tin is obtained from cassiterite by reduction with coke. Use the data given below to determine the minimum temperature (in $K$) at which the reduction of cassiterite by coke would take place.
At $298 \ K$: $\Delta_{f}H^{\circ}(SnO_{2(s)}) = -581.0 \ kJ \ mol^{-1}$,$\Delta_{f}H^{\circ}(CO_{2(g)}) = -394.0 \ kJ \ mol^{-1}$
$S^{\circ}(SnO_{2(s)}) = 56.0 \ J \ K^{-1} \ mol^{-1}$,$S^{\circ}(Sn_{(s)}) = 52.0 \ J \ K^{-1} \ mol^{-1}$
$S^{\circ}(C_{(s)}) = 6.0 \ J \ K^{-1} \ mol^{-1}$,$S^{\circ}(CO_{2(g)}) = 210.0 \ J \ K^{-1} \ mol^{-1}$
Assume that the enthalpies and the entropies are temperature independent.

Which of the following has the lowest percentage of carbon?

From argentite $(Ag_2S)$ ore,the method used in obtaining metallic silver is:

Explain the extraction/purification of copper.