Question

(b) Metals like Al, Ca, Na etc can
be used as reducing agents to extract
metals. Give one example and
Explain.​

Answer 1

Answer:

example is Al used as reducing agent in Fe2O3,extraction of iron and with Mn3O4

Answer 2

Explanation:

Reduction of metal oxides into metals is a important process involved in the extraction of metals i.e. metallurgy. We generally use Carbon in the form of coke for the reduction.

But beside this, we also use displacement reactions to reduce the metals. The highly reactive metals such as Sodium, calcium, Aluminium etc. are used for displacing the metals of lower reactivity. Here, when aluminium is used, it is known as Aluminothermy or Thermite process.

Let's see some examples:

We know that metals like Chromium, manganese, Vanadium are all less reactive than Aluminium. They are obtained by the reduction of oxides with Al powder (Used here). Some reactions are:

• $\sf{3MnO_2 + 4Al \: \: \underrightarrow{heat} \: \: 3Mn + 2Al_2O_3 + Heat}$

• $\sf{Cr_2O_3 + 2Al \: \: {\underrightarrow{heat}} \: \: \normalsize{2Cr + Al_2O_3 + Heat}}$

Here a large amount of heat is released. Hence, it is an exothermic reaction. It is known to us because metal is in molten state. One of its application is:

• It is used in welding the railway tracks and cracked machine parts. The reaction between Iron oxide and aluminium is used.

And we are done !!