Skip to main content

What is Standard Electrode Potentials

Measured cell emf are the mainly the basis for standard electrode potentials. chemistry assignments

A method for the presentation of the data obtained from measurements of the equilibrium emf of electrochemical cells must now be developed. One expects (a thermodynamic proof of this is given in the description) that varying the concentration of any reagents involved in the electrode process will affect the emf of the cell. In view of this, the emfs of the cell with the reagents at standard states are reported. In keeping with standard states introduced with these standard state conditions are again chosen to consist of gases at unit activity, implying for most gases approximately 1 bar pressure, and solutes also at unit activity. For solutes, which for electrochemical cells are frequently ions, the activities can be appreciably different from molar concentrations. How activity coefficients can be determined to recognize that a standard state is chosen and that the emf’s that cells would have for their variable reagents at unit activity are tabulated.

It is impractical, however, to list the emf’s of all possible combinations of electrodes. It would be much more convenient to have some means of tabulating the relative electron accepting powers of the individual electrodes. This can be done by tabulating the emf of cells composed of a selected reference electrode and a variety of other electrodes. Quite arbitrarily, it is agreed that the hydrogen electrode, with a hydrogen pressure of 1 bar and a unit hydrogen ion activity in the solution, will be used as the reference electrode.

Tabulations can then be given of the emf measured for cells with the standard hydrogen electrode on the left and another electrode on the right. For example:

Pt| H2 (1 bar)| HCl (a = 1) | Cl2 (1 bar) | Pt

The emf of this particular cell is found to be + 1.3592 V and it is this value which is given for the Pt| Cl2 |Cl- electrode.

Such tabulated values also are interpreted as electrode emf’s based on a zero emf being assigned to the reference hydrogen electrode. If the value is for all reagents at unit activity, such electrode potentials are known as standard electrodes potentials, indicated by the symbol €˚. The results for the hydrogen chlorine cell can now be interpreted by recalling that the reported cell emf of +1.3592 V corresponds to the process in which electrons are gained from the external circuit by the right electrode and delivered to the external circuit by the left electrode.

Comments

Popular posts from this blog

Awesome Ways To Kick-Start Your Creativity

     The brain power is exhausting so much on paper, projects and exams, that’s typical for our well of creativity to run dry and if it does then it’s essential to identify how we can restock it by motivation to reignite that creative spark. Tutorsglobe is releasing pressure of these hectic schedule providing extremely talented tutor's service.             Have you experienced writer’s block, suffered through a dry spell or had your creativity completely flat line? There is don’t matter what profession you’re in or where you are in life, there will be times when your capability to make something new hits the wall. every and any creative juices that were once flowing dry up and you find yourself struggling to create something… just anything.              Brain impairment can affect at any time and in any situation, but generally bring up its ugly head when t...

Improvement and excellence in Higher Education

A lot is varying in higher education. Most essentially, apprentice themselves are changing. Subsequent to long decades of ruling out, college access has extended opportunities for minority students, first-generation students and low-income students. In this year students are more probable to attend community college than any other postsecondary alternative and more probable to be older and living away from campus and may be joining part-time while balancing work as well as family. The symbolic picture of an 18-year-old high school graduate walking across a blossoming campus toward her dorm room no longer reflects the actuality of today’s college student. Institutions of higher education are act in response to these changes, partially by making course delivery more pliable. Technology has prepared this even further possible, introducing teaching as well as learning that is less forced by time and place. Technology is as well making new kinds of embedded assessment and adaptive curriculu...

Contribution of Quantitative Techniques to Managerial Economics

 Contribution of Quantitative Techniques to Managerial Economics   Mathematical Economics and Econometrics are utilised to construct and estimate decision models useful in determining the optimal behaviour of a firm. The former helps to express economic theory in the form of equations while the latter applies statistical techniques and real world data to economic problems. Like, regression is applied for forecasting and probability theory is used in risk analysis. In addition to this, economists use various optimisation techniques, such as linear programming, in the study of behaviour of a firm. They have also found it most efficient to express their models of behaviour of firms and consumers in terms of the symbols and logic of calculus. Thus, Managerial Economics deals with the economic principles and concepts, which constitute 'Theory of the Firm'. The subject is a synthesis of economic theory and quantitative techniques to solve managerial decision problems. It is rn...