Question

When aluminum oxide (\[A{{l}_{2}}{{O}_{3}}\]) is electrolyzed for the production of aluminum metal. For a given quantity of electricity, the number of moles of aluminum obtained if the volume of oxygen \[{{O}_{2}}\] gas obtained is 201.6 liter measured at NTP is________________.
a.) 9
b.) 6
c.) 12
d.) 4.5

Answer 1

Hint: Aluminum oxide (\[A{{l}_{2}}{{O}_{3}}\]) undergoes electrolysis and forms aluminum and oxygen as the products at the end of the process by applying some amount of electricity.

Complete step by step answer:
In the question it was mentioned that aluminum metal is going to be produced by the electrolysis of aluminum oxide.
We have to calculate the quantity of electricity (Q) needed to electrolyze the aluminum oxide.
 First we will calculate the number of equivalents of oxygen produced.
Number of equivalents of oxygen
\[\begin{align}
  & =\dfrac{201.6}{5.6} \\
 & =36 \\
\end{align}\]
Equivalent volume of oxygen = 5.6 liter at NTP.
Therefore, number of equivalents of aluminum = 36
Mass of aluminum = 36 \[\times \] 9 g
Number of moles of aluminium
\[\begin{align}
  & =\dfrac{\text{mass of aluminium}}{\text{molar mass of aluminium}} \\
 & =\dfrac{\text{36 }\!\!\times\!\!\text{ 9}}{\text{27}} \\
 & =\text{ 12} \\
\end{align}\]
So, the answer is 12.
So, the correct answer is “Option C”.

Additional Information:
Generally Alumina is available in nature in the form of bauxite.
Bauxite is an ore that is mined from topsoil in various tropical and subtropical regions.
In 1887 a process discovered called the Bayer process. It is the primary process by which alumina can be extracted from bauxite.

Note: Don’t be confused with the words alumina and aluminum oxide. Both are the same.
Alumina is the common name given to aluminum oxide.
The molecular formula of aluminum oxide is \[A{{l}_{2}}{{O}_{3}}\].