What are galvanic cells and explain its working?, Chemistry

Assignment Help:

The device through which chemical energy is converted into electrical energy is known as galvanic cell or electrochemical cell or voltaic cell. In a galvanic cell, a redox reaction is carried out in an indirect manner and the decrease in free energy process appears as electrical energy. An indirect redox reaction is such that reduction and oxidation processes are carried in separate vessels. In order to understand this phenomenon, let us consider the Zn - CuSO4 reaction as the basis of the cell reaction.


In its simple form, a zinc strip is dipped in the ZnSO4 solution and copper strip is dipped in the CuSO4 solution taken in separate beakers. The two metallic strips which act as electrodes are connected by the stripes conducting wires through a voltmeter. The two solutions are connected through a reversed U-tube known as salt bridge. The U-tube is filled with the solution of some electrolyte such KCl, KNO3 or NH4Cl to which gelatin or agar-agar has been added to convert it into semi-solid paste. A schematic of this cell has been shown.

The deflection in voltmeter shows that there is a potential difference between the two electrodes. It has been establish that the conventional current flows from the outer circuit from copper to zinc strip. It means that the electrons flow occurs from zinc to copper strip.

Let us now understand the working of the cell.

(i) Zinc undergoes oxidization to form zinc ions

Zn(s)  258_halides.png  Zn2+(aq) + 2e- (oxidization)

(ii) The electrons liberated during oxidization are pushed through the connecting wires to copper strip.

(iii) Copper ions move towards copper strip, pick up the electrons, and get reduced to copper atoms which hare deposited at the copper strip.

(iv) Cu2+(aq) + 2e-  258_halides.png  Cu(s) (reduction)

The electrode at which oxidization occurs is anode and that at which reduction occurs is cathode. In the above that, zinc strip is anode and the copper strip is cathode. Due to the oxidization process occurring at the anode it becomes a source of electrons and acquires a negative charge in the cell. Similarly, due to the reduction process occurring at the cathode it acquires positive charge and becomes a receiver of the electrons. Thus the electrochemical cell, anode electrode acts as negative terminal and cathode electrode acts as a positive terminal.

 

 

 


Related Discussions:- What are galvanic cells and explain its working?

Thermodynamics, entropy change in mixing ideal gas

entropy change in mixing ideal gas

Structure of organic molecules, state the purification processes commonly u...

state the purification processes commonly used by organic chemists to separate different components from a mixture

Dipole moment, why dipole moment of CH3CL is more than CH3F

why dipole moment of CH3CL is more than CH3F

Calculate the expected enthalpy of hydrogenation, Calculate the expected en...

Calculate the expected enthalpy of hydrogenation of a six-membered ring with three double bonds and compare it with the value obtained in 74.1. What is the reason for this diffe

Coating of metals, ramesh wants to coat the below silver articles with gold...

ramesh wants to coat the below silver articles with gold suggest the suitable coating process for ramesh to choose for coating the articles and justify the reason for the chosen me

Shiff base, i am synthesing the azipines and i wana to fet the azipine with...

i am synthesing the azipines and i wana to fet the azipine with different subsituites. how can i get with triflouro subsituited azipines?

Inorganic chemistry, dipole moment of para.nitro aniline is 6.10 D.why

dipole moment of para.nitro aniline is 6.10 D.why

Orbital angular momentum of an electron in 2s -orbital, The orbital angular...

The orbital angular momentum of an electron in 2s -orbital is: (1) 1/2 h/ 2Π                              (2) h/ 2Π (3) √2 h/ 2 Π                      (4) Zero Ans

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