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The data below tabulates standard electrode potentials (E°), in volts relative to the standard hydrogen electrode (SHE), at: Temperature 298.15 K (25.00 °C; 77.00 °F); Effective concentration (activity) 1 mol/L for each aqueous or amalgamated (mercury-alloyed) species; Unit activity for each solvent and pure solid or liquid species; and
Hydrogen embrittles a variety of metals including steel, [19] [20] aluminium (at high temperatures only [21]), and titanium. [22] Austempered iron is also susceptible, though austempered steel (and possibly other austempered metals) displays increased resistance to hydrogen embrittlement. [23]
During the early development of electrochemistry, researchers used the normal hydrogen electrode as their standard for zero potential. This was convenient because it could actually be constructed by "[immersing] a platinum electrode into a solution of 1 N strong acid and [bubbling] hydrogen gas through the solution at about 1 atm pressure".
Hydrogen gas is a reducing agent when it reacts with non-metals and an oxidizing agent when it reacts with metals. 2 Li (s) + H 2 (g) → 2 LiH (s) [ a ] Hydrogen (whose reduction potential is 0.0) acts as an oxidizing agent because it accepts an electron donation from the reducing agent lithium (whose reduction potential is -3.04), which ...
Group 1 and group 2 metals in compounds have OS = +1 and +2, respectively. Hydrogen has OS = +1 but adopts −1 when bonded as a hydride to metals or metalloids. Oxygen in compounds has OS = −2 but only when not bonded to oxygen (e.g. in peroxides) or fluorine.
The most reactive metals, such as sodium, will react with cold water to produce hydrogen and the metal hydroxide: 2 Na (s) + 2 H 2 O (l) →2 NaOH (aq) + H 2 (g) Metals in the middle of the reactivity series, such as iron , will react with acids such as sulfuric acid (but not water at normal temperatures) to give hydrogen and a metal salt ...
The oxidation states are also maintained in articles of the elements (of course), and systematically in the table {{Infobox element/symbol-to-oxidation-state}} See also [ edit ]
Hydrogen damage is the generic name given to a large number of metal degradation processes due to interaction with hydrogen atoms. Note that molecular gaseous hydrogen does not have the same effect as atoms or ions released into solid solution in the metal.