Give reasons why:
Aluminium cannot be extracted by the reduction of its ores.

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Solution

Aluminium cannot be reduced from its ore as:
In the extraction of the aluminium from its bauxite ore, first it is converted to sodium aluminate known as alumina.
The melting point of alumina is $2000 {}^{\circ}C$ and it is a poor conductor of heat so it cannot be directly reduced to form pure aluminium.
So, to the alumina the addition of cryolite, fluorspar and coke is done.
By addition of these substances the melting point reduces to $900 - 950 {}^{\circ}C$ .
Due to the high melting point and poor conduction of heat, aluminium is not extracted by reduction of its ores.

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