Dry cell cathode reaction?? (1 Viewer)

[Bobbo1]

Ok, I've seen so many different ones, and I dont know which one is right??

 

[Aquawhite]

At the anode: Zn(s) → Zn2+(aq) + 2e- [e° = -1.04 volts]

At the cathode: 2MnO2(s) + 2 e- + 2NH4Cl(aq) → Mn2O3(s) + 2NH3(aq) + H2O(aq) + 2 Cl- [e° ≈ +.5 v]

 

[zxreth]

Cathode Reaction: 2MnO2(s) + 2NH4+ + 2e- --> Mn2O3 (s) + H2O(l) + 2NH3

Source: Jacaranda

 

[Aquawhite]

Yep, exactly as what I've written, however you're removed the spectator ions. Either equation is perfectly fine for the exam.

 

[Bobbo1]

Thats what I though as well, but in cssa 2011 it is: NH4+(aq) + MnO2(aq) + e-(aq) --> NH3(aq) + MnO(OH)(s)
and I've seen something different from these 2 as well..

p.s. thanks for the quick reply

 

[Aquawhite]

Thats what I though as well, but in cssa 2011 it is: NH4+(aq) + MnO2(aq) + e-(aq) --> NH3(aq) + MnO(OH)(s)
and I've seen something different from these 2 as well..

p.s. thanks for the quick reply

I think any combination of those substances would be correct. Perhaps CSSA has given the active form, while most other texts give the final reduced state. I would just go with what you know.

 

[Bobbo1]

ok, thanks mate!