1.

Following flow diagram represent the extraction of aluminium form bauxite. Select the incorrect statement.

Answer»

Bauxite is purified by Hall's , Serpeck's and Baeyer's processes
In electrochemical process for aluminium extraction , a molten mixture of `Al_2O_3,Na_3AIF_6 and CaF_2` is USED as electrolyte
`AL(OH)_3` is converted into anhydrous alumina by calcination process
None

Solution :(A),(B) and (C )are correct statements.
(A)Red bauxite CONTAINING the impurity of oxide of iron is removed by using Hall's and Baeyers methods while white bauxite containing the impurity of silica is removed by using serpeck's method.
(B)`Na_3AlF_6and CaF_2` lowers th melting point and increase the electrical conductivity of molten `Al_2O_3`
(C )`2Al(OH)_3underset("In absence of air")overset(Delta)to Al_2O_3+3H_2O(g)darr`. It is CALLED as calcination process.


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