In a thermite process, the reducing agent is

Al

The correct answer is option 4. Al.

The thermite process is a highly exothermic reaction in which a metal oxide is reduced by a more reactive metal to produce molten metal and an oxide slag. The most common thermite reaction involves the reduction of iron(III) oxide (\(Fe_2O_3\)) by aluminum (\(Al\)) to produce iron and aluminum oxide (\(Al_2O_3\)).

The chemical equation for the thermite reaction involving iron(III) oxide and aluminum is:

\(Fe_2O_3(s) + 2Al(s) \rightarrow 2Fe(l) + Al_2O_3(s) \)

In this reaction:

• Iron(III) oxide (\(Fe_2O_3\)) is the metal oxide, acting as the oxidizing agent.
• Aluminum (\(Al\)) is the reducing agent, providing electrons to reduce iron(III) oxide and undergo oxidation itself.
• The reaction is highly exothermic, releasing a large amount of heat as the products are formed. This makes it useful for applications such as welding, metal cutting, and incendiary devices.

Now, let us delve into the role of aluminum as the reducing agent in the thermite process:

1. Reducing Agent: A reducing agent is a substance that donates electrons to another substance (the oxidizing agent) during a chemical reaction. In the thermite reaction, aluminum serves as the reducing agent. When aluminum reacts with iron(III) oxide, it donates electrons to reduce iron(III) ions to iron metal:

\[ 2Al(s) \rightarrow 2Al^{3+}(aq) + 6e^- \]

\[ Fe_2O_3(s) + 6e^- \rightarrow 2Fe(l) + 3O^{2-}(aq) \]

2. Oxidation of Aluminum: As aluminum donates electrons, it undergoes oxidation, losing electrons to form aluminum ions:

\[ 2Al(s) \rightarrow 2Al^{3+}(aq) + 6e^- \]

3. Reduction of Iron(III) Oxide: Iron(III) oxide gains electrons from aluminum, resulting in the reduction of iron(III) ions to iron metal:

\[ Fe_2O_3(s) + 6e^- \rightarrow 2Fe(l) + 3O^{2-}(aq) \]

4. Overall Reaction: The net reaction combines the oxidation of aluminum and the reduction of iron(III) oxide:

\[ Fe_2O_3(s) + 2Al(s) \rightarrow 2Fe(l) + Al_2O_3(s) \]

5. Heat Release: The thermite reaction is highly exothermic, releasing a large amount of heat energy as the products are formed. This heat is sufficient to melt the iron produced, resulting in a molten pool of iron.

In summary, aluminum serves as the reducing agent in the thermite process, donating electrons to reduce iron(III) oxide to iron metal while undergoing oxidation itself. This reaction releases a significant amount of heat energy and is used for various industrial and military applications.