Chemical Properties
Small crystals or powder, colorless and shiny. Contains approximately 69% silver and turns gray when exposed to light. Melts at 652°C and decomposes at 1,085°C. Partially dissolves in water and completely dissolves in solutions containing ammonium hydroxide, nitric acid, sulfuric acid, and hot water. Does not dissolve in alcohol. Its solubility in pure water is low, but it increases when the pH of the solution decreases. When the concentration of H+ ions is high enough, it can dissolve significantly.
Uses
Silver sulfate is used as a catalyst to oxidize long chain aliphatic hydrocarbons in the determination of chemical oxygen demand (COD). It serves as a catalyst in wastewater treatment and aids in the production of nanostructured metallic layers beneath Langmuir monolayers.
Application
Silver sulfate may be employed in the following studies:
Iodination reagent in combination with iodine for the synthesis of iododerivatives.
Synthesis of iodinated uredines.
Preparation
Silver sulfate is precipitated by adding sulfuric acid to a solution of silvernitrate:2Ag+(aq) + SO42- (aq) → Ag2SO4 (s) The precipitate is washed with hot water and preparation is under ruby red illumination.
General Description
Silver sulfate is an odorless white to gray solid. Sinks and mixes with water. (USCG, 1999)
Reactivity Profile
Silver sulfate has weak oxidizing or reducing powers. Redox reactions can however still occur. The majority of compounds in this class are slightly soluble or insoluble in water. If soluble in water, then the solutions are usually neither strongly acidic nor strongly basic. These compounds are not water-reactive.
Health Hazard
Contact with eyes causes irritation. If continued for a long period, ingestion or inhalation of silver compounds can cause permanent discoloration of the skin (argyria).
Purification Methods
Crystallise the sulfate form hot conc H2SO4 containing a trace of HNO3, and dilute with H2O while being strongly cooled. The precipitate is filtered off, washed with H2O and dried at 120o. Its solubility in H2O is 0.8% at 17o, and 1.46% at 100o. Store it in the dark. [Glemser & Sauer in Handbook of Preparative Inorganic Chemistry (Ed. Brauer) Academic Press Vol II p 1042 1965.]
