1. Tardigrade
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  3. Chemistry
  4. In the extraction of aluminium Process X: employed for red bauxite to remove iron oxide (main impurity) Process Y: (Serpeck's process): used for white bauxite to emove Z (main impurity) then. Select correct option for the process X and impurity Z.

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Q. In the extraction of aluminium
Process X: employed for red bauxite to remove iron oxide (main impurity)
Process Y: (Serpeck's process): used for white bauxite to emove Z (main impurity) then. Select correct option for the process X and impurity Z.

General Principles and Processes of Isolation of Elements

Solution:

(X) Red bauxite contains the impurities of oxides of iron and silicates. In Bayer process, alumina is dissolved by reacting sodium hydroxide solution leaving behind the insoluble oxide of iron.
(Y) White bauxite contains the impurity of silica which is removed by Serpeck’s method.
$Al_{2}O_{3}+N_{2} + 3C \xrightarrow{1800^{o}C} 2AlN + 3CO;$
$SiO_{2} + 2C \xrightarrow{1800^{o}C} Si + 2CO$
$AlN + 3H_{2}O \to Al(OH)_{3} + NH_{3};$
$2Al(OH)_{3} \xrightarrow{\Delta} Al_{2}O_{3} + 3H_{2}O$