1. 2j Preparing and analysing

2. Last lesson tests for cations
Li+, Na+, K+, Ca2+ using flame tests
NH4+ using NaOH(aq)
Cu2+, Fe2+ and Fe3+ using NaOH(aq)

3. Flame tests Ion Colour of flame Li+ Scarlet Na+ Yellow K+ Lilac Ca2+
Brick red

4. Testing for NH4+ (“ammonium ion”)
Add NaOH (aq)
Warm gently
Test gas given off with damp red litmus
Ammonia gas is given off which turns the damp red litmus BLUE.

5. Testing for Cu2+, Fe2+ and Fe3+ using NaOH(aq)

6. Testing for Cu2+, Fe2+ and Fe3+ using NaOH(aq)
Metal ion
Result of adding NaOH (aq)
Cu2+
Pale blue precipitate of Cu(OH)2
Fe2+
Dirty green precipitate of Fe(OH)2
Fe3+
Rusty brown precipitate of Fe(OH)3
Common hydroxides (EXCEPT Na, K and NH4) are INSOLUBLE so form precipitates

7. Today’s lesson
chloride, bromide and iodide, using dilute nitric acid and silver nitrate solution
sulphate, using dilute hydrochloric acid and barium chloride solution
sulphite, using dilute hydrochloric acid and identifying the sulphur dioxide evolved
carbonate, using dilute hydrochloric acid and identifying the carbon dioxide evolved

8. Precipitation reactions
Reactions that produce an INSOLUBLE SALT

9. Testing for Cl-, Br- and I- ions

10. Testing for Cl-, Br- and I- ions
Add SMALL amounts of silver nitrate solution to salts containing halogen ions that have been dissolved in dilute nitric acid.
Type of ion (dissolved in HNO3(aq))
Result of adding dilute silver nitrate
Cl-
Br- I-

11. Testing for Cl-, Br- and I- ions
Add SMALL amounts of silver nitrate solution to salts containing halogen ions that have been dissolved in dilute nitric acid.
Type of ion (dissolved in HNO3(aq))
Result of adding dilute silver nitrate
Cl-
White precipitate of silver chloride
Br-
Cream precipitate of silver bromide I-
Pale yellow precipitate of silver iodide

12. Testing for sulphate ions SO42-(aq)
Add SMALL amounts of barium chloride solution to salts containing sulphate ions that have been dissolved in dilute hydrochloric acid.

13. Testing for sulphate ions SO42-(aq)
Add SMALL amounts of barium chloride solution to salts containing sulphate ions that have been dissolved in dilute hydrochloric acid.
If sulphate ions are present, a white precipitate of barium sulphate is formed.

14. Testing for sulphite ions SO32-(aq)
Add dilute hydrochloric acid.
Test the gas given off for sulphur dioxide by passing through pink acidified potassium manganate solution which turns colourless.

15. Testing for carbonate ions CO32-(aq)
You know this one!

16. A recap! Acid + base salt + water Acid + metal salt + hydrogen
Acid + carbonate salt + water + carbon dioxide
The salt made by sulphuric acid is a metal sulphate
The salt made by hydrochloric acid is a metal chloride
The salt made by nitric acid is a metal nitrate

17. Testing for carbonate ions CO32-(aq)
You know this one!
Add dilute hydrochloric acid
Test the gas given off for carbon dioxide (turns limewater “milky”)