Why is electrolysis needed to extract aluminum from its oxide?

Answer 1

The bond between the aluminum and its oxide is very strong.

Aluminium is also high up in the reactivity series; using the displacement method requires highly reactive elements at high temperatures to extract the aluminum (not practical).

You have to use electrolysis to extract aluminum because... Aluminium is higher than carbon in the reatvity series where carbon reduces the oxide from zinc iron tin etc.... so you need to use electrolysis to remove the oxygen from the aluminum ore. Hoped this help :)

Answer 2

The most common ore of Iron is haematite Fe2O3. The most common ore of aluminium is Bauxite Al2O3. Although the formulae are very similar, Aluminium is a much more reactive metal than Iron and therefore bonds onto the oxygen in the ore much more strongly than Iron does. This means that more energy is required to break the Al/O bonds than the Fe/O bonds and extract the aluminium. Therefore iron can be extracted from haematite simply by heating the haematite with carbon as carbon is more reactive than iron and will react with the oxygen in haematite leaving the free iron. However, carbon is not reactive enough to do the same in bauxite,, because aluminium is more reactive than carbon, and so aluminium can only be extracted using large quantities of electrical energy - huge currents passed through a solution of bauxite in molten cryolite (another aluminium ore), when aluminium metal and oxygen are produced.

this difference can be dramatically demonstrated by a pyrite reaction between Fe2O3 and Al2O3 The Thermit reaction shows the difference in reactivity well: Aluminium powder and powdered haematite Fe2O3 are mixed and set light to. The reaction is incredibly violent and almost explosive creating clouds of white aluminium oxide and leaving iron metal, as aluminium, being more reactive, competes for, and wins, the oxygen from the iron. The heat produced can rse the temperature to several thousands of degrees - well hot enough to melt the iron. This reaction is used where small quantities of molten iron are needed in remote areas e.g. welding together isolated railway lines. Another example of just how reactive aluminium is can be demonstrated by its oxidation in air. Aluminium, when scratched, immediately reacts with the air forming an oxide layer that is reasonably transparent and cannot be seen. This layer then protects the aluminium underneath from further reaction. So on face value, aluminium seens very inert so that it can be used for wrapping chocolate ('silver paper') , cooking foil, bottle tops, drinks cans and so on. However, if the aluminium is dipped into a solution of Mercury nitrate the oxide layer is removed by the solution and a reaction happens that makes the oxide layer unable to reform. If the aluminium is then dried and held in the air, within seconds it will start to get coated in white alumium oxide, gets very hot, and within a few minutes will be reduced to a white ash of aluminium oxide.

Answer 3

Magnetite (Fe3O4) and hematite (Fe2O3), the two principle forms of iron ore, are far more easy to convert into molten iron than bauxite (Al(OH)3) is. This is because the lattice energy of bauxite is a lot greater than the lattice energy of either of the iron ores. For iron, you can usually just smelt away the oxygen by heating it with charcoal, which reacts with the oxygen to form CO2 and leaves the molten iron behind. For aluminum, you pretty much have to electrolyze it to get aluminum metal because there are no real oxides that are more favorable to form than aluminum ones.

Answer 4

Coz, aluminium oxide has ionic properties,the bond between aluminium ion and oxide ion is strong...moreover,aluminium's atomic mass is high...so electrolysis is required to extract aluminium from its oxide.

Answer 5

Cause you need to :)

Answer 6

Because it is highly reactive.