A dry cell is a chemical battery in which no free liquid is present, the electrolyte being soaked up by some absorbent material such as cardboard. A primary, or voltaic, cell produces electricity by means of a chemical reaction but is not rechargeable to any great extent. The conventional dry cell (e.g., flashlight or transistor-radio battery) is a primary cell.
a dry cell
Whether it is your watch, clock, toy, torch or a camera,you must have used dry cells to operate them. So, we should know about what does dry cell is made of ?
A carbon-zinc cell consists of a cylindrical vessel made of zinc.A carbon rod with a brass cap is placed at the centre of this vessel. Zinc acts as the negative electrode and carbon as the positive electrode.A paste of ammonium chloride, zinc chloride, manganese dioxide and carbon is filled in the vessel around the carbon rod.The paste is surrounded by another paste of Plaster of Paris, ammonium chloride and zinc chloride.The zinc vessel is closed with a layer of pitch. Finally, the vessel is wrapped with a thin cardboard and we have a carbon-zinc dry cell.
This cell is a primary cell in which the electrolyte ammonium chloride is dissociated into positive and negative ions. These are attracted towards the electrodes and produce voltage.When they are connected with a wire , current begins to flow.In this reaction,hydrogen gas is also produced and it is converted into water by manganese dioxide is used up,to convert hydrogen into water.After this conversion, the cell produces no electricity.
But why are these cells called dry cells ? I t is because its electrolyte is nit in solution form but in a paste form. It would become useless the moment the electrolyte dries up. High temperatures adversely affect dry cells. Hence , they should be kept away from direct sunlight. Its better to takeout cells from the torchlight, camera, or transsister,if they are not being used because moisture leaks out from the cell and it swells up.
But why are these cells called dry cells ? I t is because its electrolyte is nit in solution form but in a paste form. It would become useless the moment the electrolyte dries up. High temperatures adversely affect dry cells. Hence , they should be kept away from direct sunlight. Its better to takeout cells from the torchlight, camera, or transsister,if they are not being used because moisture leaks out from the cell and it swells up.
