What are galvanic cells ? Explain the woriking of a galvanic cell with a neat sketch taking Denicell cell as example.

Explanation

Galvanic cell : A device which converts chemical energy into electrical energy by the use of spontaneous redox reaction is called Galvanic cell (or) voltaic cell. Eg: Daniell cell.
Daniell cell : It is a special type of galvanic cell. It contains two half cells in the same vessel. The vessel is devided into two chambers. Left chambers is filled with `ZnSO_(4)` (aq) solution and Zn - rod is dipped into it. Right chamber is filled with aq. `CuSO_(4)` solutin and a copper rod is dipped into it. Process diaphragm acts as Slat bridge. The two half cell's are connected to external battery.
Cell reactions:
Ion `Zn//ZnSO_(4)` half cell, oxidation. reaction occurs
`Zn to Zn^(2+) +2e^(-)`
Ion `Cu//CuSO_(4)` half cell, reduction reaction occurs.
`Cu^(+2) +2e^(-) +2e^(-)`
The net cell reaction is
`Zn +Cu^(+2) hArr Zn^(+2) +Cu`
Cell is represented as `Zn//Zn^(+2)||Xu^(2+)//Cu`