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(A) Incorrect. The electrochemical extraction of aluminum (Hall-Heroult process) is performed at temperatures around $900-1000^{\circ} C$,not $>2500^{

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$B, C, D$

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(A) Incorrect. The electrochemical extraction of aluminum (Hall-Heroult process) is performed at temperatures around $900-1000^{\circ} C$,not $>2500^{\circ} C$.$(B)$ Correct. The sodium aluminate solution is neutralized by passing $CO_2$ gas to precipitate hydrated alumina: $2Na[Al(OH)_4]_{(aq)} + 2CO_{2(g)} \rightarrow Al_2O_3 \cdot 3H_2O_{(s)} \downarrow + 2NaHCO_{3(aq)}$.$(C)$ Correct. Concentration of bauxite (Bayer's process) involves the dissolution of $Al_2O_3$ in hot aqueous $NaOH$: $Al_2O_3(s) + 2NaOH(aq) + 3H_2O(l) \rightarrow 2Na[Al(OH)_4](aq)$.$(D)$ Correct. The electrolysis of $Al_2O_3$ is performed in a mixture with $Na_3AlF_6$ (cryolite) and $CaF_2$ to lower the melting point and increase conductivity,producing $Al$ at the cathode and $CO_2$ at the anode.

List-$I$	List-$II$
$A$. Calcination	$1$. Galena
$B$. Roasting	$2$. Magnetite
$C$. Magnetic separation	$3$. Pyrometallurgy
$D$. Carbon reduction of metal oxide	$4$. Malachite

The electrochemical extraction of aluminum from bauxite ore involves:

Similar Questions

Which of the following reactions is $NOT$ entropy-driven with reference to extractive metallurgy? (unbalanced reactions)

Select the correct statement.

Match the items of List-$I$ with those of List-$II$ and choose the correct option given below.
List-$I$ List-$II$
$A$. Calcination $1$. Galena
$B$. Roasting $2$. Magnetite
$C$. Magnetic separation $3$. Pyrometallurgy
$D$. Carbon reduction of metal oxide $4$. Malachite

Write the uses of alloys.

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