Qualitative analysis: anions

A/L Chemistry · G.C.E. Advanced Level · Grades 12–13

Aim

To identify anions using simple tests.

Apparatus

• Test tubes and a dropper
• Dilute HCl, BaCl₂, AgNO₃, NH₃
• FeSO₄ and conc. H₂SO₄

Method

1. Add dilute HCl: note any gas and its test.
2. Add BaCl₂ then dilute HCl.
3. Add AgNO₃ then dilute NH₃.
4. Do the brown ring test for nitrate.
5. Identify the unknown anion.

Conclusion

CO₃²⁻ gives CO₂ with acid; SO₄²⁻ a white BaSO₄ insoluble in acid; Cl⁻ white, Br⁻ cream, I⁻ yellow silver halides; NO₃⁻ the brown ring.