Mercury silvering Mercury silvering Mercury silvering or fire gilding is a silvering technique for applying a thin layer of precious metal such as silver or gold (mercury gilding) to a base metal object. The process was invented during the Middle Ages and is documented in Vannoccio Biringuccio's 1540 book "De la pirotechnia". An amalgam of mercury and the precious metal is prepared and applied to the object which is then heated, sometimes in oil, vaporizing most of the mercury. The technique is dangerous since mercury is highly toxic, especially in its vapor phase. Mercury silvering can be detected through a variety of
Alkaline battery With mercury content reduced by law and improvements in the purity and consistency of materials, manufacturers have reduced the mercury content in modern cells. In an alkaline battery, the negative electrode is zinc and the positive electrode is manganese dioxide (MnO). The alkaline electrolyte of potassium hydroxide is not part of the reaction, only the zinc and MnO are consumed during discharge. The alkaline electrolyte of potassium hydroxide remains, as there are equal amounts of OH consumed and produced. The half-reactions are: Overall reaction: The chemical energy is stored mostly in the zinc metal, whose cohesive free energy per atom