How A PH Probe Works - . For some elements, the predominance area for a given oxidation state may disappear completely above or below a given pH If the element is in an intermediate oxidation state, the element will undergo disproportionation at appropriate pH's. Eh–pH diagram: Eh–pH diagram, any of a class of diagrams that illustrate the fields of stability of mineral or chemical species in terms of the activity of hydrogen ions (pH) and the activity of electrons (Eh) Consequently, the reactions illustrated on Eh–pH diagrams involve either proton transfer (eg,. In the process world, pH is an important parameter to be measured and controlled The pH of a solution indicates how acidic or basic (alkaline) it is. Attention: Pour des raisons de sécurité, les expériences décrites dans les documents ne doivent être effectuées que par un professeur dans un laboratoire de Physique-Chimie. Areas in the Pourbaix diagram mark regions where a single species (Fe 2+ (aq), Fe 3 O 4 (s), etc) is stable More stable species tend to occupy larger areas. A pH meter takes advantage of this and works like a voltmeter: it measures the voltage (electrical potential) produced by the solution whose acidity we're interested in, compares it with the voltage of a known solution, and uses the difference in voltage (the "potential difference") between them to deduce the difference in pH. YouTube TV - No long term contract Loading Household sharing included Live TV from 60+ channels No cable box required Cancel anytime Working No thanks Try it free Find out why Close .