Video Transcript
Fill in the blank. In the extraction of aluminum, the
aluminum blank are blank because they blank electrons. (A) Atoms, oxidized, lose. (B) Atoms, reduced, lose. (C) Ions, oxidized, gain. (D) Ions, reduced, lose. (E) Ions, reduced, gain.
To answer this question, let’s look
at how aluminum is extracted.
Aluminum is found in an ore named
bauxite. Bauxite is made up of a large
amount of aluminum oxide with other metal oxides. First, the aluminum oxide, which is
called alumina, once it is purified is extracted from the other metal oxides using
the Bayer process. Alumina has a very high melting
point, making it challenging to work with. However, the aluminum metal can be
separated from the alumina. This is done by reducing the
aluminum using electrolysis in the Hall–Héroult process.
Since each answer choice has
“oxidized” or “reduced,” let us discuss these words in terms of electrons. Oxidation is a chemical reaction
where a chemical species loses electrons. And reduction is a chemical
reaction where a chemical species gains electrons.
In alumina, Al2O3, the aluminum
ions have a three-plus charge. They start as ions, since they are
in an ionic compound. Then, the aluminum ions are reduced
when each ion gains three electrons to form atoms of aluminum metal. This can be seen in the following
half equation. Al3+ plus three electrons yields to
produce aluminum.
Filling in the blanks in the
sentence, we can see that the correct answer is (E). In the extraction of aluminum, the
aluminum ions are reduced because they gain electrons.
