Question

In dry cell ........... acts as positive terminal.

• A. carbon rod
• B. manganese dioxide
• C. manganese dioxide and powdered carbon
• D. metal cap on the carbon rod

Answer 1

Answer: (D)

metal cap on the carbon rod

Dry cells contain a Zinc container which itself acts as a negative electrode. The moist paste is made from a mixture of plaster of Paris, Ammonium Chloride, and Zinc Chloride called sal ammoniac paste. This forms the electrolyte of the cell and takes up the major amount of volume in the battery.

The carbon rod forms the positive electrode. It is coated with MnO2 and powdered carbon. The powdered carbon reduces the internal resistance of the cell. Metal cap on carbon rod make positive terminal.

Thus Option D is correct.