What are the various types of electrodes?, Chemistry

Some important types of electrodes which are frequently used in electrochemical cells are described as follows:    

Metal-metal ion electrode: such type of electrodes includes a metal rod dipped in the solution of its own ions. Some examples areZn/Zn2+, Ag/Ag+, Cu/Cu+ etc.
    
Amalgam electrodes: these are similar to metal-metal ion electrodes, but here the metal is used in the form of its amalgam with hg. Amalgam is formed to modify the activity of metal. (An-Hg)/Zn2+ is one of the common examples of this type.
    
Gas electrodes: such electrodes involve inert metal such as platinum dipped in the solution containing ions of the gaseous element. The arrangement is made in such a manner that gas and its ions are brought in contact at the surface of the inert metal. Some examples along with their electrode reactions are as follows:

Hydrogen electrode   :    Pt, H2(g)/H+(aq)
H2  1326_electrode potential.png  2H+ + 2e-              or 2H+ + 2e-  1326_electrode potential.png  H2
Chloride electrode    :    Pt, Cl2(g)/Cl-(aq)
2Cl-  1326_electrode potential.png  Cl2 + 2e-            or Cl2 + 2e-  1326_electrode potential.png  2Cl-
Bromine electrode     :   Pt, Br2(g)/Br-(aq)
2Br-  1326_electrode potential.png  2Br2 + 2e-          or Br2 + 2e-  1326_electrode potential.png  2Br-

    
Metal-metal insoluble salt-salt anion: in such electrodes, the metal and some sparingly soluble salt of metal are dipped in aqueous solution of some other soluble salt whose anion is same as that of sparingly soluble salt of the metal. One of the common examples is Ag-AgCl(s)/KCl(aq). Here, silver and sparingly soluble salt of Ag, i.e. AgCl is put in aqueous solution of KCl. The concentration of Ag+ions in KCl solution is controlled from the knowledge of Ksp of AgCl as follows.

1280_electrode potential1.png 

The electrode reactions are as follows:

Ag(s) + Cl-(aq)  1326_electrode potential.png  AgCl + e            oxidization
    
AgCl(s) + e-  1326_electrode potential.png  Ag(s) + Cl-(aq)      reduction 


Another important example of this type of electrode is calomel electrode: Hg-Hg2Cl2(s)/KCl(aq), whose electrode reactions are:

2Hg(l) + 2Cl-(aq)  1326_electrode potential.png  Hg2Cl2(s) + 2e-      oxidization  
  
Hg2Cl2(s) + 2e-  1326_electrode potential.png  2Hg(l) + 2Cl-(aq)       reduction
    

Redox electrodes: these electrodes include a platinum wire dipped in a solution of a mixture of two salts of the same metal having different oxidation states. Some ordinary examples are listed below:
 
Pt, Fe2+/Fe2+ Fe2+  1326_electrode potential.png  Fe2+ + e-

Or, Fe2+ + e-  1326_electrode potential.png  Fe2+

Pt, Sn2+/Sn4+ Sn2+  1326_electrode potential.png  Sn4+ + e-

Or, Sn4+ + 2e-  1326_electrode potential.png  Sn2+

 

 

 

 

Posted Date: 6/26/2012 2:18:09 AM | Location : United States







Related Discussions:- What are the various types of electrodes?, Assignment Help, Ask Question on What are the various types of electrodes?, Get Answer, Expert's Help, What are the various types of electrodes? Discussions

Write discussion on What are the various types of electrodes?
Your posts are moderated
Related Questions
A covalent bond between two atoms is formed by which of the following: (1) Electron nuclear attraction  (2) Electron sharing  (3) Electron transfer (

Physical properties of dienes

Chemical properties of monohydric alcohols Characteristic reaction of alcohol are the reaction of the - OH group. The reactions of the hydroxyl group includes either cleavage o

Choose the best definition of temperature

The number of appositively charged ions surrounded a certain ion in an ionic crystal lattice is known as co- ordination number.

The principal quantum number represents : (1) Shape of an orbital (2) Distance of electron from nucleus (3) Number of electrons in an orbit (4) Number of orbitals in an

Although cholrine is electron withdrawing group.yet it is ortho nd para directing in electrophilic aromatic substitution reactants.why? Solution) Halogens are an exception of th

Inversion of cane-sugar : The hydrolysis of sucrose through boiling along with a mineral acid or through enzyme invertase, generates a mixture of equal molecules of D-glucose

Nomenclature of special compounds Unbranched assemblies that involve two or more identical hydrocarbon units joined via a single bond are named by placing a appropriate numeri

Q. Catalytic activity of metalloenzymes? Catalytic activity of metalloenzymes depends on the complex form in ability of a particular metal ion. One specific example is carbonic