Question

The reagent used to leach alumina from bauxite in Bayer's process is:

• A. NaOH
• B. NaCl
• C. HCl
• D. KCl

Answer 1

The correct option is A NaOH

Bayer's process is used in the industrial production of aluminium from the bauxite ore. The bauxite ore is grounded finely and then concentrated by the process of leaching. NaOH is the reagent used in this process to leach the grounded bauxite ore as it selectively leaches alumina by the following reaction.

${\text{Al}}_2{\text{O}}_3{\text{.2H}}_2\text{O}\left(s\right)\text{+ 2NaOH}\left(\mathrm{aq}\right)\underset{\mathrm{Pressure}}{\overset{\mathrm{Heat}}{\to }}{\text{2Na}}^{}{\text{AlO}}_2\left(\mathrm{aq}\right){\text{+ 3H}}_2\text{O}\left(l\right)$