Q. In purification of bauxite by hall’s process
A) Bauxite ore is fused with $Na_{2}CO_{3}$
B) Bauxite ore is heated with $NaOH\$solution at $50℃\$
C) Bauxite ore is heated with $NaHCO_{3}$
D) Bauxite ore is fused with coke and heated at 1800$℃$ in a current of nitrogen
Explanation
(a)
In Hall’s process
$Al_{2}O_{3} \bullet 2H_{2}O + Na_{2}CO_{3}\ \longrightarrow 2NaAlO_{2} + \ CO_{2} + 2H_{2}O$
$2NaAlO_{2} + \ 3H_{2}O + CO_{2}\ \overset{333K\ }{\rightarrow}\ \ 2Al(OH)_{3} \downarrow + \ Na_{2}CO_{3}$
$2Al(OH)_{3}\ \overset{1473K\ }{\rightarrow}\ \ Al_{2}O_{3} + 3H_{2}O$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.