I am doing a school project on cyclic voltammetry and am currently studying the topic. I have learnt that the reaction mostly takes place around the working electrode where the current is measured together with the counter/auxiliary electrode. My question is, how does the counter/auxiliary electrode pass current without oxidising or reducing the analyte?
For example, I were to increase the potential in a solution of $\ce{Fe^3+}$ ions. The working electrode would be the cathode and would reduce the ions, giving them electrons and forming $\ce{Fe^2+}$ ions. In this case, what would happen around the counter electrode? How would the electrode be able to pass current to balance it? Would it oxidise the newly formed $\ce{Fe^2+}$ ions? Wouldn't this result in a never ending process? If someone has already asked this question, I apologize. Please link the page, thank you.