Leclanche Cell Assignment Help | Leclanche Cell Homework Help

Leclanche Cell

This cell was invented by Leclanche, French electrician and therefore is called the Leclanche cell. It consists of a glass vessel containing saturated solution of ammonium chloride (NH4CI) celled sal ammoniac, as electrolyte, zinc rod as negative electrode and porous pot having carbon rod (acting as positive electrode)  surrounded by powdered carbon and black oxide of manganese (MnO2) acting as depolarizer. When the carbon rod and the zinc rod are connected, an eclectic current flows form carbon rod to zinc rod, the chemical acting taking place is given below:

     Leclanche Cell

Zinc reacts with ammonium chloride solution forming zinc chloride and liberating hydrogen and ammonia according to chemical reaction

Zn + 2NH4CI → ZnCI2 + H2 + 2NH3

Ammonia (NH3) being soluble dissolve in the solution and hydrogen before going to carbon rod enters the porous pot reacts with MNo2 forming brown oxide of manganese (Mn2O3) and water according to chemical reaction H2 + 2MnO2- Mn2O3 + H2O .

As the action of the cell depends the presence of manganese dioxide, the cell works so long as he whole of dioxide is not rescued to browse of manganese by the action or hydrogen. The polarization stats after the cell has been continues service its rate of oxidation by MnO2. It the cell is disconnected and left to itself it becomes depolarized, and reviver is original strength due to the fact that manganese oxide takes oxygen from air and becomes manganese dioxide again. Hence such cells can pot be used for continues service and are only used for in services such as ringing electric bells, telephone etc. The e.m.f. is about 1.5 volts and internal resistance is high due to proud pot. During operation water addle periodically of maintain the electrolyte level, and the zinc electrode if replaced when worn out.

Advantages: (i) No chemical action takes place so long as the current is not drawn format, (ii) It is very cheap and requires little attention and (iii) no diffusion takes place.

Disadvantages: (i) High retinal resistance due to porous pot. 

For more help in Leclanche Cell click the button below to submit your homework assignment