Halide ions – identification with AgNO₃
ChemistryInorganic ChemistryAges 15–16Virtual lab
Use it with your class: students open it from a link or a QR code, with no account needed.
Next in Inorganic Chemistry
Add AgNO₃ solution to samples of NaF, NaCl, NaBr and NaI. The simulation shows the correct precipitate colour for each (white AgCl, pale yellow AgBr, yellow AgI, no precipitate for F⁻) and lets you follow up with excess NH₃ — only AgCl redissolves, which is exactly how the four ions are told apart in the lab.
Lesson: Hydrogen halides and halide salts
What it shows
Halide ions are identified by the silver halide they form with Ag⁺. AgCl, AgBr and AgI are insoluble and differ in colour, from white through pale yellow to yellow, while AgF is soluble, so fluoride gives no precipitate. Because the colours of AgBr and AgI are easy to confuse, a second test with ammonia is used: AgCl dissolves in excess NH₃ as the complex ion [Ag(NH₃)₂]⁺, AgBr only partly dissolves and AgI does not. Both trends follow the falling solubility from AgCl to AgI.
How to use
Pick a Solution in the tube, then click Add AgNO₃ and note the precipitate. Click Add excess NH₃ to confirm, and Rinse tube before the next sample. Turn on Show ionic equation once students have described what they see. For a quick assessment, choose Hidden sample – guess: students run both tests, decide which halide ion is present and then check the verdict.
Parameters you can change
- Solution in the tube NaF, NaCl, NaBr, NaI, Hidden sample – guess
- Show ionic equation
Questions to explore
- Why can AgNO₃ solution not be used on its own to detect F⁻ ions?
- What is the ionic equation for the reaction when AgNO₃ is added to NaBr solution?
- How can excess NH₃ be used to tell an AgCl precipitate from an AgBr precipitate?
