Question

Aluminium is obtained from \[{\text{A}}{{\text{l}}_{\text{2}}}{{\text{O}}_{\text{3}}}\] by
A) Thermal reduction
B) Hydrometallurgical method
C) Electrolytic reduction
D) Reduction by iron

Answer 1

Hint: We need to know that in chemistry, periodic tables play a vital role. In the periodic table totally \[118\] elements. In the periodic table totally \[18\] columns and \[7\] rows. The columns are called as groups. Hence, \[18\] groups in the periodic table. The rows are called periods. Hence, the total \[7\] period in the table. Aluminium is present in the second period and thirteenth group in the periodic table. The atomic number of aluminium is \[13\].

Complete answer:
\[{\text{2A}}{{\text{l}}_{\text{2}}}{{\text{O}}_{\text{3}}}{\text{ + 3C}} \to {\text{4Al + 3C}}{{\text{O}}_{\text{2}}}\]
We need to remember that the aluminium be extracted from alumina (\[{\text{A}}{{\text{l}}_{\text{2}}}{{\text{O}}_{\text{3}}}\]) by electrolytic reduction method.
Cathode and anode are important for the electrolysis reduction method. Here aluminium is deposited on the cathode and oxygen is deposited on the anode. In this electrolytic reduction method electrolysis is carried out by the iron tank. It is lined with a cathode made up of carbon atoms.
Aluminium is obtained from \[{\text{A}}{{\text{l}}_{\text{2}}}{{\text{O}}_{\text{3}}}\] by electrolytic reduction only.
Hence, option A is not correct, Aluminium is obtained from \[{\text{A}}{{\text{l}}_{\text{2}}}{{\text{O}}_{\text{3}}}\]not by thermal reduction.
Option B is not correct, Aluminium is obtained from \[{\text{A}}{{\text{l}}_{\text{2}}}{{\text{O}}_{\text{3}}}\] not by hydrometallurgical method.
Option C is correct, Aluminium is obtained from \[{\text{A}}{{\text{l}}_{\text{2}}}{{\text{O}}_{\text{3}}}\] by electrolytic reduction.
Option D is correct, Aluminium is obtained from \[{\text{A}}{{\text{l}}_{\text{2}}}{{\text{O}}_{\text{3}}}\] not by reduction by air.

Note:
We also need to know that the reduction reaction means the removal of oxygen or the addition of hydrogen or the gain of electrons. The like charges repel each other and unlike charges attract each other in the electrolysis. The charge of cathode is negative and charge of anode is positive. The charge of cation is positive and the charge of anion is negative. The cathode attracts towards cation and anode attracts towards anion in the electrolytic cell by using electrolyte.