Question

Why is silver nitrate called lunar caustic ?

Answer 1

Silver nitrate is an inorganic compound with chemical formula $AgN{O_3}$ . This salt is a versatile precursor to many other silver compounds, such as those used in photography. It is far less sensitive to light than the halides. It consists of an ionic bond between the silver cation ($Ag^+$) and the nitrate anion ($NO_3^–$). Due to the ionic nature of this compound, it readily dissolves in water and dissociates into its constituent ions.

Complete answer:
Silver nitrate is a precursor to many compounds of silver, including the silver compounds used in photography. When compared to silver halides, which are used in photography due to their sensitivity to light, $AgN{O_3}$ is quite stable when exposed to light . Lunar caustic is an effective oxidizing agent for many organic compounds . It kills microorganisms and reacts with the compounds in human flesh. Thus, it is used for removing warts, destroying damaged or diseased tissues, and for stopping superficial bleeding. Silver nitrate is a chemical known for its antiseptic properties. Silver nitrate is called lunar caustic because when it comes in contact with organic substances (e.g., skin , clothes) and is reduced to metallic silver which is white like the iron lunar. Its chemical formula is $AgN{O_3}$ . Applied to the skin and mucous membranes , silver nitrate is used either in stick form as lunar caustic (or caustic pencil). The alchemists believed that silver was associated with the moon. They called silver luna (from Latin Luna = "the Moon"), so their name for silver nitrate was "lunar caustic".

Note:
Silver nitrate is a precursor to many compounds of silver, including the silver compounds used in photography. When compared to silver halides, which are used in photography due to their sensitivity to light, $AgN{O_3}$ is quite stable when exposed to light. : Silver nitrate is an inorganic compound. Silver nitrate is an oxidant and must, therefore, be kept away from organic compounds.