Depending on the type of electrode that we use, this will have a trend to suffer oxidation or reduction, that is, each one has one ' ' fora' ' of attraction for electrons, that case an electrode is connected with as an electrode whose its ' ' fora' ' it is lesser in comparison with that one, this will donate to its electrons (oxidation), and the first one will receive loads negative (reduction). To this force we call potential (e), that we can measure for each type of electrode, from an electrode standard: the hydrogen electrode. Connecting to this the diverse electrodes, we can arrive at a potential standard (E0) for each one. If for example, an electrode gains electrons (it is scrumbled) it has a E0 of reduction in comparison to the electrode standard (hydrogen). In case that now to place an electrode that donates to electrons to the electrode standard, it has the E0 of oxidation. Knowing the potential of each electrode it can to foresee, when on, who will go to suffer oxidation and who will suffer reduction. For example, an electrode X has the equal E0reduo to? 1,9 v; it will be on to electrode Y that has the equal E0reduo to? 3,2v.
Who will go to scrumble itself? Good, as electrode X has one ' ' tendncia' ' greater to scrumble itself of what Y, it will be scrumbled, whereas this is become oxidate. From this concept of potential, and that as we saw, when we establish connection different electrodes, with its respective different potentials, both ' ' disputaro' ' who will go plays the role of oxidant agent (that one who suffers reduction) and of reducing agent (who suffers oxidation). To define this, we must know which is the difference of ' ' fora' ' between them, that is, it appears an essential largeness for the agreement of the effectiveness of one determined stack: the potential difference (DDP).