Intermediate Topic 707 of 1102 Inorganic Chemistry
Qualitative Analysis of Anions
Tests such as silver nitrate for halides and barium chloride for sulfates identify anions.
In-depth explanation of Qualitative Analysis of Anions
Anion analysis identifies anions such as carbonate, sulfate, halides, nitrate and sulfite using simple precipitation and gas-evolution tests. Carbonate releases carbon dioxide with dilute acid, which turns limewater milky. Sulfate is detected by barium chloride, which gives white barium sulfate that is insoluble even in strong acid. Halides are tested with silver nitrate, giving silver chloride (white), silver bromide (cream) or silver iodide (yellow). Nitrate is identified by the brown ring test with iron(II) sulfate, and sulfite decolourizes acidified permanganate.
Going deeper: Qualitative Analysis of Anions
Key ideas: Preliminary tests with dilute H2SO4: CO3 2- gives CO2 (lime water milky), S2- gives H2S (lead acetate paper black), SO3 2- gives SO2, NO2- gives brown fumes. With conc H2SO4: Cl- gives HCl, Br- gives brown Br2, I- violet I2, NO3- brown NO2 with Cu. Confirmatory: Cl- with AgNO3 white soluble in NH3, SO4 2- with BaCl2 white insoluble in acid, PO4 3- with ammonium molybdate yellow, NO3- by brown ring test with FeSO4.
Common mistakes and connections: Students mix up sulfite and sulfate: BaSO3 dissolves in acid, BaSO4 does not. Chloride is tested only after removal of carbonate or sulfite which also precipitate. Nitrite also gives brown ring, so remove with urea or sulfamic acid first. Links to solubility rules, redox behavior of conc H2SO4 and acid-base reactions.
Visualization of Qualitative Analysis of Anions
Titration-style acid-base tests help identify anions such as carbonate; adding acid to carbonate releases CO2 as the pH falls. The interactive lesson shows this as a live animation or chart.
Worked example and use case
Adding silver nitrate to a chloride solution gives a white precipitate that dissolves in dilute ammonia.
Frequently asked questions about Qualitative Analysis of Anions
What is Qualitative Analysis of Anions?
Tests such as silver nitrate for halides and barium chloride for sulfates identify anions.
Is Qualitative Analysis of Anions a beginner, intermediate or advanced topic?
Qualitative Analysis of Anions is a intermediate topic in Inorganic Chemistry. It builds on the vocabulary of beginner topics in this area.
What should I learn before Qualitative Analysis of Anions?
Study these earlier topics in Inorganic Chemistry first: Chlorophyll, Cisplatin, Qualitative Analysis of Cations.
What comes after Qualitative Analysis of Anions?
The next topics in Inorganic Chemistry are Pigments and Dyes and Ceramics.
Can I practise Qualitative Analysis of Anions with quizzes?
Yes. The interactive lesson includes a self-check question on Qualitative Analysis of Anions, and the Inorganic Chemistry quiz draws on every topic in this area.
Where Qualitative Analysis of Anions fits in Inorganic Chemistry
Qualitative Analysis of Anions is topic 92 of 113 in Inorganic Chemistry.