Electrochemical cells, Chemistry

Assignment Help:

ELECTROCHEMICAL CELLS

Galvanic and electrolytic cells:

The difference between potential of the two metals results in a potential difference (also called a electromotive force or voltage, emf) between the two half-cells. That can be measured by means of a high impedance voltmeter which measures the driving force or voltage for reaction without allowing current to flow from which can be calculated thermodynamic data. Alternatively the reaction can be allowed to proceed by connecting the two half-cells by circuit (a wire or a resistor) and allowing the current to flow. These are both examples of galvanic cells, where the chemical reaction occurs. Electrons flow from the electrode with the most negative potential (the anode, where oxidation occurs) to that with the most positive potential (the cathode, where reduction occurs). The salt bridge (or porous glass frit) allows ions to transfer into each half-cell. That flow counteracts the imbalance of charge that would develop in each half cell as electrons (e-) pass from one electrode to the other, which would inhibit the reaction. The need for a frit or salt bridge is avoided if both half cells can share a common electrolyte. It is a special case, where all redox active ions in the solution react at one half cell electrode only and therefore do not have to be separated from the other electrode.

1024_electrochemical cells.png

Fig. 1. Examples of (a) an electrolytic cell incorporating a salt bridge; (b) a galvanic cell incorporating a porous frit.

Other half-cell reactions:

The metal-insoluble salt electrode consists of a metal M coated with a porous insoluble salt MX in a solution of X-. A good example is the silver/silver chloride electrode (Fig. 2a) for which the half-cell reaction is, where the reduction of solid silver chloride produces solid silver and releases chloride ion into solution.

 

 

2232_other half reaction.png

Fig. 2. (a) The silver/silver chloride half-cell; (b) the ferric (Fe3+)/ferrous (Fe2+) half-cell; (c) the

fluorine/fluoride ion half-cell.


Related Discussions:- Electrochemical cells

What is the packet of energy called, What is the packet of energy called: ...

What is the packet of energy called: (1) Electron          (2) Photon    (3) Positron                 (4)Proton Ans:  Photon

The interionic attraction depends on interaction, The interionic attraction...

The interionic attraction depends on interaction of: (1) Solute-Solute                             (2)  Solvent-Solvent     (3) The charges        (4) Molecular proper

.ethanol, general methods of preparation of ethanol

general methods of preparation of ethanol

Why conduction band overlaps with valence band in mg, Because Mg is metal. ...

Because Mg is metal. We know from the properties of the metal it will mallable, ductile, and good conductor for electricity. So, for better conduction the conduction band must over

How nomenclature would be easy to do?, 1.First find the maximum number of c...

1.First find the maximum number of carbons chain.Give it to as a parent name. 2.Next find functional groups and give numbering.(Functional group must get minimum number) 3.Ne

Chemical combination, the verification of the law of chemical combination

the verification of the law of chemical combination

The electronic configuration of an element with atomic no., The electronic ...

The electronic configuration of an element with atomic number 7  i.e. nitrogen atom is; (1) 1s 2 , 2s 1 , 2p 3 x                               (2)  1s 2 , 2s 2 , 2p 2 x ,

Azeotropic distillation - purification of organic compounds, Azeotropic Dis...

Azeotropic Distillation - Purification of organic compounds Azeotropic mixture is a mixture comprising constant boiling point. The most well known instance is a mixture of

Determine electron will have four quantum numbers, Be's 4th electron will h...

Be's 4th electron will have four quantum numbers:           n       l         m          s (1)     1       0         0        +1/2 (2)     1       1        +1      +1/2

Uses of phenol - hydrocarbon, Uses of Phenol - Hydrocarbon Phenol is ex...

Uses of Phenol - Hydrocarbon Phenol is extensively used in industry. The important applications of phenol are (i) Phenol is used as an antiseptic in soaps, lotions and ointm

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd