Question

In metallurgical process, aluminium acts as:
A. An oxidizing agent
B. a reducing agent
C. acidic flux
D. basic flux

Answer 1

Hint: Aluminium has a strong tendency to release it’s \[3\] electrons to achieve a stable state by getting oxidized thus aluminium acts as a good reducing agent.


Complete answer: or Complete step by step answer: In the metallurgical process, $Al$ acts as a reducing agent.
$2Al + C{r_2}{O_3} \to A{l_2}{O_3} + 2Cr + Heat$
Here, $Al$ reduces $C{r_2}{O_3}$ to $Cr$
Aluminium acts as reducing agent because when it releases electrons those electrons will go to some other stuff and reduce it, when it comes to metallurgy aluminium is used to reduce iron oxide into iron and itself getting oxidized to aluminium oxide (The thermite reaction). In this reaction the iron is mostly guided into gaps to fill them, thus calling it thermite welding.
Metallic aluminium $\left( {Al} \right)$ is of interest as a reducing agent because of its low standard potential (reduction potential).
However, its surface is invariably covered with a dense aluminium oxide film which prevents its effective use as a reducing agent in wet chemical synthesis.
Aluminium has strong affinity for oxygen and is thus readily oxidized. It thus reduces a large number of metal oxides to metals.
\[F{e_2}{O_3} + 2Al \to A{l_2}{O_3} + 2Fe\]
$\Delta H = negative$
$C{r_2}{O_3} + 2Al \to A{l_2}{O_3} + 2Cr$
$\Delta H = negative$
We can also understand the $Al$ reducing agent behavior through the following reaction.
$3Mn{O_2} + 4Al \to 3Mn + 2A{l_2}{O_3} + Heat$
This reduction reaction of manganese dioxide with aluminium is a highly exothermic reaction.
So, the correct answer is “Option B”.

Note: Aluminium is a powerful reducing agent i.e. has great affinity for oxygen, hence, it reduces the metallic oxides below it like iron oxides, with evolution of a lot of heat.