Galvanic cell or Voltaic cell | Daniel cell | chapter | Electrochemistry class 9th | kpk

Galvanic Cell The electrochemical cell in which a spontaneous chemical reaction takes place and generates electric current is called galvanic or voltaic cell. Example of this type of cell is a Daniel cell. A galvanic cell consists of two cells, each called as half-cell, connected electrically by a salt bridge. In each of the half-cell, an electrode is dipped in 1 M solution of its own salt and connected through a wire to an external circuit. Figure.7.3 shows a typical galvanic cell. The left half-cell consists of an electrode of zinc metal dipped in 1 M solution of zinc sulphate. The right half cell is a copper electrode dipped in I M solution of copper sulphate. Salt bridge is a U shaped glass tube. It consists of saturated solution of strong electrolyte supported in a jelly type material. The ends of the U tube are sealed with a porous material like glass wool. The function of the salt bridge is to keep the solutions of two half cells neutral by providing a pathway for migration of ions. Working of the Cell The Zn metal has tendency to lose electrons more readily than copper. As a result oxidation takes place at Zn-electrode. The electrons flow from Zn-electrode through the external wire in a circuit to copper electrode. These electrons are gained by the copper ions of the solution and copper atoms deposit at the electrode. The respective oxidation and reduction processes going on at two electrode.