Question

White bauxite is purified by:

• A. Bayer's process
• B. Hoop's process
• C. Serpeck's process
• D. Hall's process

Answer 1

The correct option is C Serpeck's process

White bauxite containing the impurity of silica only in removed by heating with coke in atmosphere of nitrogen.
$A{l}_2{O}_3+3C+N_2\stackrel{\Delta }{\to }2AlN+3CO$

$Si{O}_2+2C\stackrel{\Delta }{\to }Si+2CO\uparrow$;

$AlN+H_{2}O\to Al(OH{)}_3+N{H}_3$;

$2Al(OH{)}_3\stackrel{\Delta }{\to }A{l}_2{O}_3+H_{2}O$

Other process are used for extraction of $Al$ from red bauxite.