Halide Ions Flashcards
Trend of Reducing power of halides down a group
Increases as attraction is weaker due to ions getting bigger and electrons moving further from nucleus.
There’s an extra inner electron shell and so greater shielding.
Easier to lose an electron
What does it mean to reduce something
The halide ions need to lose an electron from its outer shell.
Reaction of halides with sulfuric acid (H2SO4)
All halides react with concentrated sulfuric acid to give a hydrogen halide as a starting product
Silver nitrate solution test
For halides
- Add dilute nitric acid HNO3 to remove ions which might interfere -> carbonates
- Add silver nitrate AgNO3 solution
- Precipitate formed of the silver halide
Reagent is silver nitrate - 1st
Second reagent is dilute ammonia
Colours of precipitate identifies halide
Fluoride - no precipitate
Chloride - white precipitate
Bromide - cream precipitate
Iodide - yellow precipitate
Chloride forms slowest -> iodide fastest
Adding ammonia solutions into each silver halide has a different
Solubility in ammonia
Solubility of silver halide precipitates in ammonia
Chloride - white precipitate, dissolves in dilute NH3
Bromide - cream precipitate, dissolves in concentrated NH3
Iodide - yellow precipitate, insoluble in concentrated NH3