Search results
Results From The WOW.Com Content Network
The bottom of a pH electrode balloons out into a round thin glass bulb. The pH electrode is best thought of as a tube within a tube. The inner tube contains an unchanging 1×10 −7 mol/L HCl solution. Also inside the inner tube is the cathode terminus of the reference probe.
Potentiometry passively measures the potential of a solution between two electrodes, affecting the solution very little in the process. One electrode is called the reference electrode and has a constant potential, while the other one is an indicator electrode whose potential changes with the sample's composition. Therefore, the difference in ...
A platinum wire electrode is immersed in a saturated aqueous solution of quinhydrone, in which there is the following equilibrium C 6 H 6 O 2 ⇌ C 6 H 4 O 2 + 2H + +2e −. The potential difference between the platinum electrode and a reference electrode is dependent on the activity, +, of hydrogen ions in the solution.
The electrode potential is proportional to pH when pH is defined in terms of activity. The precise measurement of pH is presented in International Standard ISO 31-8 as follows: [ 15 ] A galvanic cell is set up to measure the electromotive force (e.m.f.) between a reference electrode and an electrode sensitive to the hydrogen ion activity when ...
Commercial reference electrodes consist of a glass or plastic tube electrode body. The electrode consists of a metallic silver wire (Ag (s)) coated with a thin layer of silver chloride (AgCl), either physically by dipping the wire in molten silver chloride, chemically by electroplating the wire in concentrated hydrochloric acid (HCl) [3] or electrochemically by oxidising the silver at an anode ...
Most electrodes work over a limited range of conditions, such as pH or temperature, outside of this range the electrodes behavior becomes unpredictable. The advantage of a pseudo-reference electrode is that the resulting variation is factored into the system allowing researchers to accurately study systems over a wide range of conditions.
In between these electrodes is the electrolyte, which contains ions that can freely move. The galvanic cell uses two different metal electrodes, each in an electrolyte where the positively charged ions are the oxidized form of the electrode metal. One electrode will undergo oxidation (the anode) and the other will undergo reduction (the cathode).
The antimony electrode has been investigated for its ability to function as a pH electrode. [1] The electrode is made of elemental antimony. The electrochemical process can be formulated as Sb 2 O 3 (s) + 6 H + + 6 e − ⇌ 2Sb(s) + 3H 2 O. The oxide, Sb 2 O 3, is present on the surface of the electrode. Although this electrode does not give ...