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General Principles and processes of Isolation of Elements
easy
Reagent used in Bayer's process of concentration of bauxite ore is :
A
$NaOH$
B
$Na_2CO_3$
C
$Ca(OH)_2$
D
$CaCO_3$
Solution
Bauxite $\left( Al _2 O _3 \cdot H _2 O \right)$ is an important ore of aluminium with large impurities and is hence first roasted and then treated with concentrated solution of caustic soda. This dissolves aluminium oxide present in bauxite due to the formation of sodium aluminate, $\left( NaAlO _2\right)$.
$Al _2 O _2 \cdot H _2 O +2 NaOH \rightarrow 2 NaAlO _2+3 H _2 O \text {. }$
Since, $NaOH$ a strong reducing agent, it is used in Bayer's process.
Standard 12
Chemistry
Similar Questions
Match column $(I)$ (process) with column $(II)$ (electrolyte)
| $(I)$ (process) | $(II)$ (electrolyte) |
| $(i)$ Downs cell | $(W)$ fused $MgCl_2$ |
| $(ii)$ Dow sea water process | $(X)$ fused $(Al_2O_3+Na_3AlF_6)$ |
| $(iii)$ Hall – Heroult | $(Y)$ fused $KHF_2$ |
| $(iv)$ Moissam | $(Z)$ fused $(40\%\,NaCl\,+\,60\%\,CaCl_2)$ |
Choose the correct alternate :
normal
