- Home
- Standard 12
- Chemistry
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
$Na[Al(OH)_4]$ and $Al_2(CO_3)_3·xH_2O$
$Al(OH)_3$ and $Al_2O_3· xH_2O$
$NaAlO_2$ and $Al_2(CO_3)_3·xH_2O$
$Na[Al(OH)_4]$ and $Al_2O_3·xH_2O$
Solution
$\mathop {A{l_2}{O_3}(s)}\limits_{Alumina} + 2NaOH\left( {aq} \right) + 3{H_2}O\left( l \right)\xrightarrow[{35 – 36\,bar}]{{473 – 523\,k}}\mathop {2Na\left[ {Al{{\left( {OH} \right)}_4}} \right]\left( {aq} \right)}\limits_{\mathop {Sodium\,\,aluminate}\limits_{\left( X \right)} } $
$2Na\left[ {Al{{\left( {OH} \right)}_4}} \right]\left( {aq} \right) + C{O_2}\left( g \right) \to \mathop {A{l_2}{O_3}x{H_2}O\left( s \right)}\limits_{\mathop {Hydrated\,alumina}\limits_{\left( Y \right)} } + 2NaHC{O_3}\left( {aq} \right)$
