Electrochemistry : placement of the RE in a 3 electrode cell

[guigui92]

Fist of all, I'd like to understand why the reference electrode (RE) has to be in contact with the analyte (i.e. immerged within the solution and in contact with the latter through a fritted glass usually). Indeed, a three electrodes system is set up so that no current can pass through the RE. Charge circulation occurs through the working and counter electrodes. Isn't the RE just a constant potential cell acting as a reference potential? Why does it thus have to be in contact with the solution?

 

Secundary question: I have read that te RE has to be placed as close as possible from de working electrode. Why is that?

 

In advance, thanks for your answers.