Describe the construction, working and usefulness of a dry Cell, with the help of a diagram.
Answers
A dry cell consists of a zinc container whose base acts as the negative electrode. The carbon rod placed at the centre with a brass cap acts as the positive electrode. This is surrounded by a mixture of manganese dioxide and charcoal in a muslin bag. The electrolyte uses is a moist paste of ammonium chloride. The outer body (excluding the base) of the zinc container is insulated with cardboard.
When the dry cell is connected in a circuit comprising a bulb, current flows in the circuit due to the chemical reaction that takes place in the cell. This makes the bulb glow. The dry cell is a primary cell and it cannot be recharged.
The construction working and uses of dry cell are as follow:---
●Dry cell is a primary cell in which once chemicals are consumed further reaction is not possible.It cannot be recharged or recycled.
●In dry cell the container is made of zinc which also serves as one of the electrodes.The other electrode is a carbon rod in centre of cell.
●The zinc container is lined with a porous paper.
●A moist mixture of ammonium chloride ,magnesium diaoxide,zinc chloride and a porous inert filler occupy space between paper lined zinc container.
●The cell is sealed with a material like wax. As cell operates zinc is oxidised to zn^+2 so at cas anode.
● The electrons are utilized at carbon rod so act as cathode as ammonium ions are reduced.
●Ammonia produced at cathode combines with zinc to form complex
●This dry cell does not have indefinite life and so is not long lasting because NH4Cl is acidic so corrodes zinc container.
● Uses of dry cell are used in watches, touch and tv remote.
Reaction and diagram of cell are in the attachment:--
