Is there a difference between standard cell potential and reduction potential in electrochemistry? Can someone explain it to me? Thank you so much
I also wanna know which of the two is the E naught that I can use in calculating E naught of a cathode.
This subject probably is one of the most confusing ones for students BECAUSE the chemistry community is divided. Here is some history that goes back approximately 70 years. I know you don't want to know all of the history BUT it will help you understand your confusion. When I was in graduate school (70 years ago), the prof that taught electrochemistry to me used oxidation potentials; i.e., metal ---> metal ion + e for which Eo (Enaught) might be + 0.5 v. Note that this actually is an oxidation potential because oxidation is the loss of electrons and the equation above is written as an oxidation because it loses electrons. I was taught that a complete chemical reaction was an oxidation half cell + a reduction half cell, the loss of electrons equaled the gain of electrons and E for the complete cell was
Enaught cell = Eoxidation + Ereduction. The tables I used were oxidation tables BUT to get the reduction part to add in above for the Eoxdn + Eredn = Enaught cell, I just reversed the sign of the oxidation half cell to get the reduction half cell. My prof was an physical/inorganic chemist and his teachings were standard for his field. Now for the confusion. Unfortunately, electrochemists used reduction potentials for all of their work and calculations. Students who learned from them used a new system. So we have spawned a generation of half and half. Most chemists understand it well enough that we can use either but you can see how confusing that can get. In the literature, especially, it was important when discussing research results to explain fully which method was being used and that was not done uniformly. Chemists complained for years about the double standard while pages and pages have been written about which was the better method. I have forgotten the exact year but somewhere in the 1970s the IUPAC (International Union of Pure and Applied Chemists) formed a committee to study this problem and in the late 70s or early 80s, or at least in that time frame, the IUPAC recommended that the reduction system be THE SYSTEM and to diminish the confusion to call the reduction system the Enaught STANDARD POTENTIAL. That tells us we are looking in the table at REDUCTION potentials. I doubt you can find an oxidation potential table now. It isn't easy, anyway. So when you look up the numbers in the tables you are using Enaught reduction potentials. I must make it clear that when you calculate Enaught CELL (that's the CELL reaction) you get the same number no matter which system was used. It's the HALF CELL potential that is different; i.e., one is the negative of the other. For the second part of the question, remember that the cathode and anode are reversed in a battery vs an electroplating bath but if you use the words STANDARD POTENTIAL everyone will know that you mean the half cell is written as a reduction. I hope this long long long explanation helps clear up the confusion. Fortunately, I have lived long enough to see this story unfold.
Yes, there is a difference between standard cell potential and reduction potential in electrochemistry.
Standard cell potential (Eºcell) refers to the measure of the voltage or electric potential difference between the two half-cells in an electrochemical cell under standard conditions. It indicates the tendency of a particular redox reaction to occur and tells us whether the reaction is spontaneous or non-spontaneous. The standard cell potential is typically measured in volts (V) or millivolts (mV).
On the other hand, reduction potential (Eºred) refers to the tendency of a half-reaction to undergo reduction at the standard conditions. It measures the electric potential difference between a half-reaction and the standard hydrogen electrode (SHE), which is used as a reference electrode with an assigned reduction potential of 0 volts.
To understand the relationship between standard cell potential and reduction potential, you need to know that the standard cell potential of a redox reaction can be calculated by simply subtracting the reduction potential of the anode (oxidation half-reaction) from the reduction potential of the cathode (reduction half-reaction) in the cell.
So, the key difference is that the reduction potential refers to the potential of a specific half-reaction, while the standard cell potential refers to the overall potential of the entire electrochemical cell.
To obtain reduction potentials or standard cell potentials for specific reactions, you can refer to tables of standard electrode potentials. These tables list the reduction potentials of various half-reactions with respect to the standard hydrogen electrode.
I hope this explanation helps clarify the difference between standard cell potential and reduction potential in electrochemistry. Let me know if you have any further questions!