electrochemistry-2,galvanic cell - voltaic cell - denial cell or electrochemical cell-structure of electrochemical cell-salt-bridge-making process-function-by study everythingsjr.

 

galvanic cell - voltaic cell - denial cell or electrochemical cell.

 

In 1780 , Alessandro Volta and in 1800 Luigi Galvani was invent a galvanic cell or voltaic cell, volta has give a voltaic pile and after that both volta and galvani respectively derive electrical energy from spontaneous redox chemical reaction .basically the galvanic cell or voltaic cell is a electrochemical cell, which produces the electric energy from chemicals or we can say spontaneous chemical reactions .

 

#alessandro volta :[wikipedia]

Alessandro Giuseppe Antonio anastasio volta was a Italian chemist and physicist.

 

Born : 18^th February 1745 [18/2/1745]                                       

 

Death : 5^th march 1827 [5/3/1827]

 

Nationality : Italian

 

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Volta was a prove that the electricity generated chemically. Also volta was known for the inventor of electric battery and methan and also known for inventor of the voltaic pile.

 

 

#Luigi galvani :[wikipedia]

Luigi galvani was a Italian physician , biologist and philosopher.

 

Born: 9^th September 1737 [9/9/1737]

 

Died : 4^th December 1798 [04/12/1798]

 

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Luigi galvani is  a known for discovery of bioelectricity or animal electricity .

 

 

Daniel's name also comes up when we study electrochemical cells. So here given information is about denial and which type of relation between electrochemical cell .

Basically the denial cell and galvanic cell both are same , both the cells are basically electrochemical cell , but there is a minor difference between galvanic and denial cell .

The  difference is given below

 

Galvanic cell	Daniell cell
In galvanic cell various types of electrodes like metal electrode, non-metal electrode and also carbon or graphite electrodes are used .	In denial cell only cu and zn electrodes are used .

# daniell  [John Frederic Daniell][wikipedia]

John Frederic Daniell , was a English chemist and physicist , they known for inventor of daniell cell.

Born : 12 march 1790 [12/03/1790]

 

Died : 13 march 1845 [13/03/1845]

 

Nationality: english  

 

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why it is called electrochemical cell ?

it is called electrochemical cell because here the electricity is produced from chemical reactions or we can say spontaneous chemical reactions.

So we can say that ,

“The device which converts chemical energy into the electric energy is called as electrochemical cell”.

 

 

 

# BASIC STRUCTURE OF ELECTROCHEICAL CELL OR GALVANIC CELL OR VOLTAIC CELL OR DAINELL CELL.

 

The basic structure of galvanic cell is given below.

 

We can easily prepare it at our lab, so here primary requirements are given.

Requirements:

Two containers or beaker,

Zn strip, [used as a electrode]

Cu strip, [used as a electrode]

Thin copper wire,                                                 

Galvano meter,

1m (molar) CuSO₄ solution,

1m(molar) ZnSO₄ solution,

Salt bridge [Note: preparation of salt bridge is given below]

Take two container and give them name container A and container B.

then take ZnSO₄  solution into container A and dip weighted Zn strip or rod.

in other container B, fill with the solution of CuSO­₄ and dip pre-weighted Cu strip or rod.

Then connect two electrodes through the galvano meter with the help of thin copper wire. When we connect two electrodes electron flow will becomes and this is measured by the galvano meter. Also galvano meter is indicate the real value of current in volt. Also we have to make connection of two container with the help of salt bridge. remember that electron flow is from anode to cathode. Oxidation will always becomes on anode that is way we can say that “the electrode at which oxidation will takes place is called anode”. And reduction will always becomes on cathode that is way we can say that “the electrode at which reduction will takes place is called cathode”. In our case electron flows from zn electrode to cu electrode. Sign for denote anode is (-) and sign for denote cathode is (+).

So the oxidation on anode and reduction on cathode and complete cell reaction is given below.

 

 As we can see after the reaction starts Zn⁺² ion will formed in the container A , by the oxidation reaction. So the entire container A is becomes positively charged due to the presence of Zn⁺² ion. Then look at the left side container B , the Cu⁺² ion will converted into Cu_(s) by the reduction, and SO₄^- ion will removed into container B, so the entire solution will becomes negatively charged . it will happened but in fact the SO₄^- ion is move from solution B to solution A through the salt bridge and it help’s to keep both the solutions electrically neutral. So the main thing is Zn⁺² ions are not flow from right to left side but so₄^- ions are moves.

After allowing for some time to run reactions , both the electrodes are taken out from containers and washed carefully and weighted after drying  , we can observed that the weight of Zn strip has decreased and weight of Cu strip is increased . it has becomes due to the above redox reaction.

 

Salt bridge:

 

Structure of salt-bridge:

 

basically salt-bridge is a U-shaped glass tube.

The main components which are filled in the glass tube(salt-bridge) is agar-agar gel+ electrolytes + water.

Electrolytes: NH₄NO₃ (K₂SO₄ , KNO₃ , KCl , NH₄Cl.)

 

How to make salt-bridge ?

Requirements:

Container or beaker,

U-shaped glass tube,

Heat source,

Electrolytes: NH₄NO₃ (K₂SO₄ , KNO₃ , KCl , NH₄Cl.) (measured),

Agar-agar gel (measured),

Water (measured).

 

Making Process:

Take one beaker and add measured agar-agar gel, electrolytes, and water.

Keep the solution on heat source and give heat at least about 20-25 minutes.

After 20 minutes dismantle the solution and keep it for cooling ,it will becomes hemi-solid , this hemi-solid material is our main and required material.

After that add this material into the taken U-shaped glass tube, pack both the sides of glass tube with the help of cotton plugs,

Our salt-bridge is ready to use, salt-bridge is dipped in such a way that “two ends of salt bridge is dipped into the both solutions”.

 

Function of salt-bridge:

The main function of salt-bridge is , to keep both the solutions electrically neutral and,

Second thing is salt-bridge is helps to connect both the solutions of half cell.

Salt-bridge is allows the movement of ions from one solution to the other solution without mixing of two solutions.

During the redox reaction ions are move through the salt-bridge, in denial cell SO₄^- is moves from container B to container A and keep both the solution electrically neutral.

 

 

 

 

 

 

 

 Electrochemistry part-1 [click here]

 

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