English

Explain the Following Methods to Protect Metals from Corrosion: Galvanization - Chemistry

Advertisements
Advertisements

Question

Explain the following methods to protect metals from corrosion:

Galvanization

Solution

Galvanization:

1) The rusting of iron can be prevented by coating the metal surface with another metal such as zinc, that is oxidized in preference to iron. This process is called galvanization.

2) If the zinc layer is scratched, even then it protects iron from corrosion as long as Fe and Zn are in contact. If Fe is oxidized to Fe2+, then Zn immediately reduces Fe2+ back to Fe.

shaalaa.com
  Is there an error in this question or solution?
2015-2016 (July)

APPEARS IN

Video TutorialsVIEW ALL [1]

RELATED QUESTIONS

What is the chemical composition of malachite?

  1. CuO . CuC03
  2. Cu(OH)2 CuC03
  3. CuO.Cu(OH)2         
  4. Cu2O . Cu(OH)2

Silica is added to roasted copper ore during smelting process to remove _______.

(A) ferrous sulphide

(B) ferrous oxide

(C) cuprous sulphide

(D) cuprous oxide


Fe2O3 is reduced to spongy iron near the top of blast furance by

(A) H2

(B) CaO

(C) SiO2

(D) CO


What is the role of cryolite in the extraction of aluminium?


What is the role of coke in the extraction of iron from its oxides?


What is the role of silica in the extraction of copper?


Which form of the iron is the purest form of commercial iron?


Name the method used for refining of copper metal.


Which of the ores mentioned can be concentrated by magnetic separation method?


Draw a neat, well labelled diagram of electrolytic cell for extraction of aluminium


What is the role of the following compound- 
SiO2 in the extraction of copper from copper pyrites?


What happens when a nickel rod is dipped into a copper sulphate solution? Justify your answer.

`[E_((Ni^(+2))/(Ni))^0 = -0.25"v" and E  _(("Cu"^(+2))/("Cu"))^0 = +0.34"v"]`


Bauxite has the composition


Which among the following statement is correct?


The most abundant metal on earth is:


Which of the following options are correct?

(i) Cast iron is obtained by remelting pig iron with scrap iron and coke using hot air blast.

(ii) In extraction of silver, silver is extracted as cationic complex.

(iii) Nickel is purified by zone refining.

(iv) Zr and Ti are purified by van Arkel method.


Which of the following reactions occur during calcination?

(i) \[\ce{CaCo3 -> CaO + CO2}\]

(ii) \[\ce{2FeS2 + 11/2 O2 -> Fe2O3 + 4SO2}\] 

(iii) \[\ce{Al2O3. {x}H2O -> Al2O3 + {x}H2O}\]

(iv)  \[\ce{ZnS + 3/2 O2 -> ZnO + SO2}\]


The main reactions occurring in blast furnace during extraction of iron from haematite are:

(i) \[\ce{Fe2O3 + 3CO -> 2Fe + 3CO2}\]

(ii) \[\ce{FeO + SiO2 -> FeSiO3}\] 

(iii) \[\ce{Fe2O3 + 3C -> 2Fe + 3CO}\]

(iv) \[\ce{CaO + SiO2 -> CaSiO3}\]


Although carbon and hydrogen are better reducing agents but they are not used to reduce metallic oxides at high temperatures. Why?


Identify a mineral for the major source of boron from the following list?


In the thermite process, the reducing agent is:


In the electrolytic process for the extraction of aluminium the electrolyte is:-


Metal always found in Free State is 


When compared to ΔG° for the formation of Al2O3 ΔG° for the formation of Cr2O3 is


Pyrolusite is ______.


Calamine and Malachite, respectively, are the ores of ______.


The ore that contains both iron and copper is ______.


Share
Notifications

Englishहिंदीमराठी


      Forgot password?
Use app×