LeClanche cells (1 Viewer)

[-::Sanni::-]

I.e. Dry cells. I know there are two types. One is alkaline but what is the other called?

... my questions are getting dumber and dumber... XP

Chemistry of Alkaline cells
-Redox reaction between Zn and Mn + equations
-Electrolyte KOH

 

[JasonNg1025]

Alkaline?

Well the redox reaction between Zn and Mn equations are...

At zinc can anode, Zn is oxidised:

Zn²⁺ _(aq) ---> Zn _(s) + 2e^-

The electrons go to the graphite cathode, where ammonium ions are reduced:

2NH₄⁺ _(aq) + 2e^- ---> 2NH_{3 (g)} + H_{2 (g)}

Maganese oxide acts as an oxidising agent to convert H₂ to water:

2MnO_{2 (s)} + H_{2 (g)} ---> H₂O _(l) + Mn₂O_{3 (s)}

Finally, zinc ions react with chloride and ammonia:

Zn²⁺_(aq) + 2NH_{3 (g)} + 2Cl^-_(aq) ---> Zn(NH₃)₂Cl_{2 (aq)} or ZnCl_{2 (aq)} + 2NH_{3 (aq)}

NET POTENTIAL 1.5V

 

[danz90]

I.e. Dry cells. I know there are two types. One is alkaline but what is the other called?

... my questions are getting dumber and dumber... XP

Chemistry of Alkaline cells
-Redox reaction between Zn and Mn + equations
-Electrolyte KOH

The KOH Electrolyte is used in button cells (silver-oxide cells).

 

[JasonNg1025]

Oh, is that all she wanted to know :O

 

[danz90]

Oh, is that all she wanted to know :O

lolz that was only ONE of the things she wanted, u covered the rest

 

[-::Sanni::-]

Thanks!

I'm really starting to hate batteries...

One more thing. I thought the chemistry of alkaline cells was this:

Anode: Zn<SUB>(s) </SUB>+ 2 OH<SUP>-</SUP><SUB>(aq)</SUB> --> Zn(OH)<SUB>2(aq) </SUB>+ 2e<SUP>-</SUP><SUB>(aq)<?xml:namespace prefix = o ns = "urn:schemas-microsoft-comfficeffice" /><o></o></SUB>
Cathode: MnO<SUB>2 (aq)</SUB> + 2e<SUP>-</SUP><SUB>(aq) </SUB>+ 2H<SUB>2</SUB>O<SUB>(l)</SUB> ---> Mn(OH)<SUB>2 (aq)</SUB> + 2OH<SUP>-</SUP>

Is the above correct and is it the same/different to button cells?

 

[Azreil]

Same anode reaction.

Cathode: Ag2O(s) + H2O(l) + 2e- -> 2Ag(s) + 2OH-