Electrolysis, examples and importance


Electric current can be conducted through a liquid or liquids by the process of electrolysis.

What is electrolysis?  Electrolysis can be defined as decomposition of a certain liquid and solution into their component parts when electricity is passed through them. 

Electrolysis cannot be discussed without talking about electrolyte, ions,   voltameter  and  electrodes.

What is electrolyte?  It can be defined as a chemical compounds in form of liquid or solutions which decompose into its components parts when electricity is passed through them. Example are Copper tetraoxosulphate VI, Tetraoxosulphate VI acid, Sodium hydroxide, Sodium chloride and many more.

Ions.   Ions can be described as positive or negative charged atom or compound. The positive ion is called cation
while negative ion is called anion
What is electrode?  Can be defined as rod or plate through which current enters or leaves the electrolyte. There are positive and negative electrodes.  The positive electrodes is called anode and the negative electrode is called cathode.

 Voltameter.  This is vessel containing electrolyte and electrode

Examples of electrolysis
 1.Electrolysis of acidulated water.
 Here electrolyte is water and few drop of tetraoxosulphate V1 acid.  The electrodes are made up of platinum.
 When steady electricity is passed through the platinum electrodes the bubbles of gases are formed at the upper end of graduated tube of Hoffmann Voltameter use in conducting electrolysis of acidulated water and the level of electrolyte fall.  The hydrogen gas is collected at a cathode while the oxygen gas is collected at the anode. 

  Equation electrolysis of acidulated water
According to ionic theory water dissociate into hydrogen ions and hydroxyl ion.  That is 
            H20 H+  + OH

  The tetraoxosulphate vi acid dissociate into hydrogen ions and tetraoxosulphate vi ions which is given as
H2SO4 →2H+ + SO42

What happens at the anode during electrolysis of acidulated

OH + e = OH

OH + OH = H2O + O

O + 0 + O2 (oxygen produced at the anode)

What happens at the cathode during electrolysis of acidulated

H+ + e = H

H + H = H2 (Hydrogen Produced at the cathode)

In the electrolysis of acidulated water using platinum electrodes,   oxygen is form at the anode and   the hydrogen is formed at the cathode. The volume of hydrogen formed is twice the volume of oxygen formed.  This is evidence that there are as twice as many hydrogen atoms as oxygen atom in water.   And it further confirmed that the chemical formula of water H20

2. Electrolysis of   copper tetraoxosulphate (vi) solution using copper electrodes 

Using an apparatus as shown in the diagram below. When electricity is being applied the copper tetraoxosulphate  vi   solutions dissociate into  copper ions  and tetraoxosulphate vi ions while water dissociate  into hydrogen ions and hydroxyl 


CuSO4 Cu2+ + SO42

H2O → 2H+ + OH
During the passage of electricity the copper and hydrogen ions move to cathode where copper is discharge in preference to hydrogen ion from water, therefore copper is deposited at cathode. 
And tetraoxosulphate vi ions and hydroxyl ion drift to anode.   Tetraoxosulphate vi ion combine with copper of the anode to form copper tetraoxosulphate vi. As copper from the anode is going into solution so is the copper from the solution is being deposited at the cathode. So the concentration of copper tetraoxosulphate (VI) remains the same.  

Importance of electrolysis

1. Electrolysis can be used in purifying of metal

2. It is used in coating of metal to avoid rusting

3. It is used in generation of electricity

4. It is used in extraction of metal

5. Electrolysis can be used to confirm that chemical formula of water is H2O

6. It can be used in separation of chemical compound

7. It can be used in production or preparation of element

8. It can be used to produce gas from a solution


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