Thermodynamically favored reaction

  • Thread starter Thread starter nipwoni
  • Start date Start date
  • Tags Tags
    Reaction
AI Thread Summary
In the discussion about the electrolysis of seawater, the focus is on determining which reaction is thermodynamically favored based on standard cell potentials. The production of H2 and O2 has a standard cell potential of -2.06 V, while the production of H2 and Cl2 has a potential of -2.19 V. The key point is that the reaction with the more negative voltage is less favored, meaning the reaction with a voltage closer to zero is thermodynamically favored. The concept of thermodynamic favorability is linked to spontaneity, which is indicated by the sign of the Gibbs free energy change (ΔG). A negative ΔG suggests a spontaneous reaction. Confusion arises from differing interpretations of voltage values, with emphasis on understanding that lower absolute values (closer to zero) indicate more favorable reactions. The discussion highlights the need for clarity in educational materials, as conflicting information from TAs and answer sheets can lead to uncertainty.
nipwoni
Messages
51
Reaction score
0
I have a homework question about the electrolysis of seawater, and I need to know what reactions are thermodynamically favored. One reaction is the production of H2 and O2, and it has a standard cell potential of -2.06 V. The other is the production of H2 and Cl2, and has a standard cell potential of -2.19 V. Is the favored reaction the one that occurs at a more negative voltage, or the one at a voltage with a smaller absolute value?
 
Chemistry news on Phys.org
What does it mean for a reaction to be "thermodynamically favored"? What is the name of the quantity that measures this ? How does that quantity relate to the variables you have in an electrochemical cell?
 
The production of hydrogen and oxygen from water is not favored thermodynamically so you can guess upon the productino of hydrogen and chlorine gas based on this.
 
But based on the voltages which will be favored over the other? I know that reactions at "lower" voltage/ cell potential are favored, but what do they mean by lower? Is it the one with an actual lower number (more negative) or the one with a voltage closer to zero? I need to know for an exam tomorrow, not just for these particular reactions. Thanks!
 
Doesn't your text say answer explicitly on these matters? I gave you hints in my post, and you should be able to figure it out.
 
Ok so it's the more negative voltage that's favored.
My book didn't say, and my problem was that I got conflicting answers from different TAs. The answer sheet to the problem set also contradicts what you said, but they're wrong sometimes (quite often actually.)
 
I somewhat forgot whether it's the negative or positive indicates spontaneity, you'll need to refer to your text to make sure.
 

Similar threads

Reaction energy for a Lithium Iron Phosphate battery
Replies
0
Views
2K
What is the true voltage of a voltaic cell?
Replies
10
Views
2K
Question about the Li -> Li+ + e- half cell reaction in a LiB battery
Replies
5
Views
8K
Electrolysis of water and actual electrode potential.
Replies
3
Views
2K
Clarification about the sign of EMF in batteries and electrochemistry
Replies
3
Views
2K
Triple electrode cell for energy storage and H2 production
Replies
1
Views
1K
Voltaic cell + battery in series
Replies
3
Views
2K
Thermodynamics of chemical reactions
Replies
28
Views
2K
Fuel Cell Reaction Question - is this right?
Replies
1
Views
1K
Entropy Changes in Electrolytic/Galvanic Cell?
2
Replies
53
Views
5K

Hot Threads

Recent Insights

Back
Top