Sacrificial metals and displacement of metals

In summary: But I believe, I have understood the concept.In summary, when trying to prevent iron from rusting, one can use a more reactive metal like magnesium to transfer electrons into the iron, reducing Fe2O3 to Fe metal. The magnesium itself will be oxidized, forming a layer of MgO around it. This is because ionic compounds form when electrons are transferred from the metal to the non-metal. The process does not require a lot of heat energy, as the electrons from the magnesium are sufficient to reduce Fe2O3. However, this method is not efficient for extracting iron from haematite ore due to impurities. Lastly, placing a wire onto a zinc block and dipping the other end into a solution of copper sulfate
  • #1
sgstudent
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When I want to prevent iron from rusting, I use a more reactive metal such as magnesium and connect it to the iron. This protects iron from being rusted as the magnesium will transfer electrons into the iron when it rusts, thus reducing Fe2O3 into Fe metal. However, Mg will be oxidised to Mg2+ but how does it get oxidised? It's electrons are transferred to the Fe2O3 already, so how does a layer of MgO form around it? Since ionic compounds form when the electrons transfer from the metal to the non metal (layman terms) so hoe does the magnesium receive its oxygen ion?

Also, I thought a lot of heat is required for Mg to displace Fe2O3? So why just a wire is needed for it to "cure" the metal. And why can't we extract iron ore Fe2O3 from this method too?

Lastly, if I place a wire onto a zinc block and dip the other end of the wire into a solution of copper sulfate, will displacement of the metal occur to form copper metal in the solution while the since forms a block of Zn2+ ions?

Thanks for the help!
 
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  • #2
sgstudent said:
When I want to prevent iron from rusting, I use a more reactive metal such as magnesium and connect it to the iron. This protects iron from being rusted as the magnesium will transfer electrons into the iron when it rusts, thus reducing Fe2O3 into Fe metal. However, Mg will be oxidised to Mg2+ but how does it get oxidised? It's electrons are transferred to the Fe2O3 already, so how does a layer of MgO form around it? Since ionic compounds form when the electrons transfer from the metal to the non metal (layman terms) so how does the magnesium receive its oxygen ion?

Also, I thought a lot of heat is required for Mg to displace Fe2O3? So why just a wire is needed for it to "cure" the metal. And why can't we extract iron ore Fe2O3 from this method too?

Lastly, if I place a wire onto a zinc block and dip the other end of the wire into a solution of copper sulfate, will displacement of the metal occur to form copper metal in the solution while the since forms a block of Zn2+ ions?

Thanks for the help!

I guess that the water present in Fe2O3 , like yes : Fe2O3.xH2O ionizes

Fe2O3 <--------------> 2Fe3+ + 3O2-
Now Mg is oxidized because of loss of electrons as well as addition of oxygen.

3Mg ----------> 3Mg2+ +6e-

2Fe3+ + 6e- ---------------> 2Fe

Hence we see that Mg reduces Fe2+ to Fe with itself being oxidized without the requirement of heat energy !

Now 3Mg + 3O2- ---------> 3MgO

Overall reaction : Fe2O3 + Mg ------> 3MgO + 2Fe

And we can not extract Fe from haematite ore by this method because its not efficient as lot of impurities remains. We prefer blast furnace method.

And what wire are you talking about in last paragraph ?

Note : I am not sure if I am cent percent correct.
 

1. What is a sacrificial metal?

A sacrificial metal is a metal that is more reactive than another metal in a chemical reaction. It is used to protect the less reactive metal from corrosion or oxidation by sacrificing itself.

2. How does the displacement of metals occur?

The displacement of metals occurs when a more reactive metal replaces a less reactive metal in a compound. This is due to the difference in reactivity and the release of energy during the chemical reaction.

3. What are some examples of sacrificial metals?

Zinc, magnesium, and aluminum are commonly used as sacrificial metals to protect iron and steel from corrosion. Other examples include tin, lead, and cadmium.

4. How does sacrificial metal protection work?

Sacrificial metal protection works by creating a galvanic cell, where the more reactive metal acts as the anode and the less reactive metal acts as the cathode. This creates a flow of electrons from the sacrificial metal to the less reactive metal, protecting it from corrosion.

5. Are there any drawbacks to using sacrificial metals?

One potential drawback to using sacrificial metals is the cost of regularly replacing them. Additionally, if the sacrificial metal is not properly maintained, it can lead to accelerated corrosion of the protected metal. Another drawback is the potential environmental impact of using certain sacrificial metals, such as cadmium, which is toxic.

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