Why the graphite rods in the extraction of aluminium from molten `Al_2O_3` have to be replaced from time to time ?

The quantity of charge requird to obtain one mole of aluminium from Al_2O_3 is

Describe the Hall-Heroult's process for the extraction of aluminium from alumina. Draw a labelled diagram for the process.

In the extraction of aluminium by Hall-Heroult process, purified Al_2O_3 is mixed with CaF_2 to

Why is the extraction of copper from pyrites more difficult than that from its oxide ore through reduction?

How does velocity-time graph give a geometrical way of calculating the distance covered from time t to time t'?

Preparation of pure alumina (Al_2O_3) from bauxide ore.

Translate the following statements into chemical equation and balance the equations : aluminium metal replaces iron from ferric oxide (Fe2O3) giving aluminium oxide and iron.

In the Hall process, aluminium is produced by the electrolysis of molten Al_2O_3 . How many second would it take to produce enough aluminium by the Hall process to make a case of 24 cans of auminium soft-drink, if each can uses 5.0g of Al, a current of 9650amp is employed and the current efficiency of the cell is 90%:

Into how many kingdoms, systematics has been divided from time to time?

What is chemical nature of Al_2O_3 ?