Dry cell and button cell batteries (1 Viewer)

[Tom2nv]

Is there one definitive answer when refering to the chemistry of both the button and the dry cell as on different webistes and in textbooks the equations regarding anode, cathode half equations and the overall equation are different depending on the source observed. I was just wondering if it was just me or is there actual mutiple equations to these cells. Any advice or extra information would be appreciated. Cheers

 

[xiao1985]

there were never an absolute answer to chemistry...

you are right, different sources will quote different equations... and chances are, they are all right ... to a certain degree...

 

[Tom2nv]

thank god i didnt really know wat to do, anyway so wat do u suggest i write up

 

[Forbidden.]

You talking about the anode and cathode reactions and overal cell equations ?

 

[xiao1985]

although sources can vary, they shouldn't vary too much...

for eg, for dry cell cathode most text books will give you:

Mn oxide + H+ + e-<----> Mn Hydroxide + H2O

the one i remembered was:

Mn O2 + 2NH4+ +2e-<---> Mn(OH)2 + 2NH3

as long as you can prove you are right (can be found in a text book), it's good to remember.

 

[Forbidden.]

although sources can vary, they shouldn't vary too much...

for eg, for dry cell cathode most text books will give you:

Mn oxide + H+ + e-<----> Mn Hydroxide + H2O

the one i remembered was:

Mn O2 + 2NH4+ +2e-<---> Mn(OH)2 + 2NH3

as long as you can prove you are right (can be found in a text book), it's good to remember.

subscipts & superscripts are teh best

Subscript

[sub ] [/sub ] Example - x₂

Superscript

[sup ][/sup ] Example - x²

Remove the spaces in the tags


So you remember:

MnO₂ + 2NH₄+ +2e-<---> Mn(OH)₂ + 2NH₃

 

[Tom2nv]

ok thanks for that im understanding it better now, although is the arrow in ur equations signifying an equilibrium reaction

 

[Forbidden.]

ok thanks for that im understanding it better now, although is the arrow in ur equations signifying an equilibrium reaction

Definitely, so you can play the Le Chatelier game ... except the dry cell can't be recharged for safety reasons
(The hydrogen gas present in the cell is highly explosive)

ALL galvanic cells undergo a equilibrium reaction otherwise they can't produce electricity !

EDIT: That stuff above was theoretical, to completely support the above, you need to constantly supply electrolytes ...