Solution Potential Witout Electrodes (Pourbaix diagram help)

In summary, the individual is trying to use SEA to plate CuCl2- onto a Titanium oxide membrane. They understand how the y-axis works in an electrochemical cell, but are unsure of the potential when there is no cell. They plan to dissolve CuCl2 in acid and want to know the potential of the solution. The potential will be 0 as long as there are no other reducing agents present.
  • #1
JasonSpata
2
0
files.php?pid=81742&aid=2099.gif
http://C:\Users\jason\Desktop\Research Summer 2016\cucl pb.PNG I am currently attempting to use SEA to plate CuCl2- on to the surface of a magneli phase Titanium oxide membrane.
I can roughly rationalize the y-axis and how it functions when there is an electrochemical cell (follow OCP), and how to calculate the potential utilizing the Nernst equation, but what if there is no Echem cell?

I will dissolve CuCl2 in acid (pH ~ .8) so the window I am aiming for in which my desired species predominates is tight. (I know the Pourbaix diagram is concentration and temperature dependent but I really just seek to understand exactly what the y-axis means)

My question is, If I dissolve x amount of CuCl2 in .5 molar HCl, (10mM CuCl2 solution) in a beaker, in ambient conditions, what would the voltage potential of the solution be? Would it just be 0? Do I need to have an Echem cell in order to have any potential at all? Any help is greatly appreciated.
 
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  • #2
Yes, as long as you don't have another reducing agent in your solution, the potential will be 0. The only relevant reducing agent I can think of is hydronium ions, But near ph=1 their potential will be approx 0 and production of hydrogen will be hindered kinetically.
 

1. What is a Pourbaix diagram and how does it help determine solution potential without electrodes?

A Pourbaix diagram is a graphical representation that shows the thermodynamic stability of different species in a solution as a function of the solution's pH and the potential of the solution. This diagram helps determine solution potential without using electrodes by providing a visual representation of the relative stabilities of different species at different pH and potential values.

2. How is a Pourbaix diagram created?

A Pourbaix diagram is created by plotting the thermodynamic potentials of different species on a two-dimensional graph with the x-axis representing the pH and the y-axis representing the potential of the solution. The stability of each species is determined based on the equilibrium constants of their reactions and the Nernst equation.

3. What information can be obtained from a Pourbaix diagram?

A Pourbaix diagram can provide information about the thermodynamic stability of different species in a solution at various pH and potential values. It can also show the regions of stability for different chemical species and the conditions (pH and potential) under which a particular species will be the most stable.

4. How can a Pourbaix diagram be used to predict corrosion?

A Pourbaix diagram can be used to predict corrosion by identifying the regions in the diagram where the potential and pH values correspond to the stability of a particular metal or alloy. If the operating conditions of a system fall within this region, it indicates that the metal or alloy may undergo corrosion.

5. Are there any limitations to using a Pourbaix diagram?

Yes, there are certain limitations to using a Pourbaix diagram. It assumes that the system is at equilibrium, which may not always be the case in real-life scenarios. Additionally, it does not take into account kinetic factors and only provides information about thermodynamic stability. Therefore, it should be used in conjunction with other techniques for a more comprehensive analysis.

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