Junior Scientist DANIELL CELL  (Multicolor)

In 1836 the British chemist John Frederic Daniell (1790-1845) proposed an improved electric cell that supplied an even current during continuous operation. Daniell cell consisted of a glass jar containing copper and zinc electrodes, each immersed in their respective acidic sulphate solutions. The two solutions were separated by a porous clay cylinder separator. It was a galvanic cell in which the spontaneous electrodis solution of zinc and electroplating of copper provided the electrical current. HOW IT WORKS When the zinc and copper electrodes are joined by wire, the following observations are made: • There is a flow of electric current through the external circuit. • The zinc rod loses its mass while the copper rod gains in mass. • The concentration of ZnSO4 solution increases while the concentration of copper sulphate solution decreases. • The solutions in both the compartments remain electrically neutral.