DEVELOPMENT OF ELECTRICITY......

DEVELOPMENT OF ELECTRICITY......

   Who had discovered first electric cell ? or, who made today's method of power generation easier? Let us have a quick view through the history of power generation.

   The first man to make a cell was Alessandro Volta in the year 1800 AD . He made a pile of  Zinc and Copper plates one after another and separating them with wet cloths dipped in Sulfuric acid. Later years electric cell was formed using the Volta's idea.

SIMPLE VOLTAIC CELL

      STRUCTURE

           Two plates one of Zinc And the other Copper is partly immersed in dilute Sulfuric Acid taken in a pot. This makes a Simple Voltaic Cell. The Copper plate becomes positive and the Zinc plate becomes negative. If we connect them with a conducting wire then electric current flows.

      WORKING

                In simple Voltaic cell Chemical energy is transformed into electrical energy. This incident was discovered by famous scientist Galvani of Italy.

   

         Change in the Solution

           Molecules of the dilute Sulfuric Acid dissociates into Hydrogen and Sulfate ions

  

                H₂SO₄↔ 2H⁺+SO₄^-2

        

Reaction at zinc Plate

              In this plate Zn atoms free two of its atomic electron and transforms into Zn ions. These electrons stay on the  Zn plate and make it negative. The Zn ions come into the solution.There it combines with Sulfate ions to form Zinc-Sulfate.

                    

                        Zn-2e↔Zn⁺² 

                               Zn⁺² + SO₄^-2  = ZnSO₄ 

       

         Reaction at Copper Plate

              The Hydrogen ions come to copper plate and take electrons from there. Hydrogen ion first turns into atom .Thus Copper plate becomes positive and Hydrogen gas is generated.

 

                        H⁺ +e=H

After this various electric cell was made. Of them Lech lance cell Lead acid cells are popular.But interesting one was the dry cells.

  DRY CELL

     To make a dry cell we need a cylinder of Zinc.Here we take Ammonium Chloride as electrolytic medium. A carbon (graphite) rod is used as the second electrode while the Zn cylinder is the first one. The electrolyte at first dissociates in to ions. Zn plays same role as in case of Simple Voltaic Cell; but this time it produces Zinc Chloride. The Carbon rod acts as copper plate in Simple Voltaic Cell. But here along with Hydrogen Ammonia is generated.

The reactions occur in the dry cell is as follows: 

NH₄Cl↔NH₄⁺+Cl^-

Zn-2e↔Zn⁺² 

Zn⁺²  + 2Cl^- =ZnCl₂ 

2NH₄⁺+2e=NH₃+H₂