Question

The mass of carbon anode consumed (giving only carbondioxide) in the production of $270kg$ of aluminium metal from bauxite by the Hall process is
(Atomic mass $Al=27$ )

• A. 180 kg
• B. 270 kg
• C. 540 kg
• D. 90 kg

Answer 1

Answer: (D)

In Hall and Heroult process
$2A{l}_2{O}_3⟶4Al+3O_2$
$4C+3O_2⟶2C{O}_2+2CO\uparrow$
$2A{l}_2{O}_3+4C⟶4Al+2C{O}_2+2CO$
Only for removal of $C{O}_2$, following equation is possible

$\because$ For $108g$ of $Al,36g$ of $C$ is required in above reaction
$\therefore$ For $270g$ of $Al$ require amount of $C$
$=\frac{36}{108}\times 270=90g$