Question

In the leaching method, bauxite ore is digested with a concentrated solution of NaOH that produces ?X?. When $CO_2$ gas is passed through the aqueous solution of ?X?, a hydrated compound ?Y? is precipitated. ?X? and ?Y? respectively are :

• A. $NaAlO_2$ and $Al_2(CO3)_3?x H_2O$
• B. $Al(OH)_3$ and $Al2O_3?x H_2O$
• C. $Na[Al(OH)_4]$ and $Al_2O_3?x H_2O$
• D. $Na[Al(OH)4]$ and $Al_2(CO3)_3?x H_2O$

Answer 1

Answer: (C)

$Na[Al(OH)_4]$ and $Al_2O_3?x H_2O$

Answer 2

$Al_{2}O_{3}+2NaOH+3H_{2}O \rightarrow 2Na\left[Al\left(OH\right)_{4}\right]$
$\left(X\right)$
$?CO_2$
$Al_2O_3\cdot xH_2O$