Q. Bauxite ore is made up of $Al_{2}O_{3} + SiO_{2} + Tio_{2} + Fe_{2}O_{3}$ This ore is treated with conc NaOH solution at 500 K and 35 bar pressure for few hours and filtered when hot. In the filtrate, the species present are
A) $NaAl(OH)_{4}\ only$
B) $Na_{2}Ti(OH)_{6}\ only$
C) $NaAl(OH)_{4}\ snd\ Na_{2}SiO_{3}both$
D) $Na_{2}SiO_{3}$ only
Explanation
(a)
In bauxite ore, only $Al_{2}O_{3}$ reacts with conc NaNO and fo sodium meta aluminate. This, further dissolves in water
$Al_{2}O_{3} + 2H_{2}O + 2NaOH\underset{35\ bar}{\overset{500\ K}{\rightarrow}}2NaAlO_{2} + 3H_{2}O$
$NaA{lO}_{2} + 2H_{2}O \rightarrow 2NaAl(OH))4\$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.