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To use electron affinities properly, it is essential to keep track of sign. For any reaction that releases energy, the change ΔE in total energy has a negative value and the reaction is called an exothermic process. Electron capture for almost all non-noble gas atoms involves the release of energy [4] and thus is exothermic.
Electrogalvanizing is a process in which a layer of zinc is bonded to steel to protect against corrosion, enhance adhesion, or give an aesthetic appeal.The process involves electroplating, running a current of electricity through a saline-/zinc-based electrolytic solution with a zinc anode and steel cathode.
This reaction is represented by Zn (s) + Cu ++ (aq) Zn ++ (aq) + Cu (s) In this redox reaction, Zn is oxidized to Zn ++ and Cu ++ is reduced to Cu. When electrons are transferred directly from Zn to Cu ++, the enthalpy of reaction is lost to the surroundings as heat. However, the same reaction can be carried out in a galvanic cell, allowing ...
In aqueous solutions, redox potential is a measure of the tendency of the solution to either gain or lose electrons in a reaction. A solution with a higher (more positive) reduction potential than some other molecule will have a tendency to gain electrons from this molecule (i.e. to be reduced by oxidizing this other molecule) and a solution with a lower (more negative) reduction potential ...
Electropositivity is a measure of an element's ability to donate electrons, and therefore form positive ions; thus, it is antipode to electronegativity. Mainly, this is an attribute of metals , meaning that, in general, the greater the metallic character of an element the greater the electropositivity.
The galvanic series (or electropotential series) determines the nobility of metals and semi-metals.When two metals are submerged in an electrolyte, while also electrically connected by some external conductor, the less noble (base) will experience galvanic corrosion.
The electrolyte provides a means for ion migration whereby ions move to prevent charge build-up that would otherwise stop the reaction. If the electrolyte contains only metal ions that are not easily reduced (such as Na +, Ca 2+, K +, Mg 2+, or Zn 2+), the cathode reaction is the reduction of dissolved H + to H 2 or O 2 to OH −. [1] [2] [3] [4]
Most side reactions occur due to the Lewis-acidity of the byproduct, ZnI 2. In reactions that produce acid-sensitive products, excess Et 2 Zn can be added to scavenge the ZnI 2 that is formed, forming the less acidic EtZnI. The reaction can also be quenched with pyridine, which will scavenge ZnI 2 and excess reagents. [24]