tags
iodine chlorideammoniaiodidesodiumiodinenitrichydrazinediphenitehydroxidesilverzinc hydroxidesilver iodide
video tutorial Make silver metal and solid iodine from silver iodide
- Goal: convert 50 g of dry silver iodide into elemental iodine and silver metal.
- Prepare aqua regia by mixing ~30 ml concentrated nitric acid with 90 ml concentrated hydrochloric acid; fresh acid recommended due to instability and toxicity.
- Add silver iodide to aqua regia to form silver chloride and oxidized iodine species; after about an hour, a yellow solid (silver chloride) forms and fumes are released; keep the mixture covered.
- Dilute with cold water to reduce fumes before filtering; wash precipitate thoroughly; the filtrate contains iodine compounds to be recovered later.
- Process filtrate to recover iodine: dilute, rest in fridge, filter iodine; further processing with water and slight neutralization yields a second batch of iodine.
- First batch iodine recovered; total iodine obtained: 21 g (78% recovery from starting AgI).
- Silver chloride is dissolved in 15% aqueous ammonia to form a soluble silver-ammonia complex; avoid concentrated ammonia to prevent silver nitride formation.
- Reduce silver in ammonia with sodium bisulfite-derived diphenite (prepared from sodium bisulfite and zinc) to yield metallic silver; filter and wash to obtain silver metal.
- Silver metal obtained: 19.9 g (87% recovery). Some residual AgI may remain for future runs.
- Alternative reducing agents (e.g., hydrazine or glucose) can work but may cause unwanted silver mirrors on glassware; observe safety concerns with all steps.
- Final products: solid iodine and solid silver metal recovered from silver iodide.
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