HSC Chemistry — Module 8
Qualitative Analysis — Flashcards & Quiz
Qualitative analysis identifies WHICH ions are present in an unknown solution (not how much), and HSC Chemistry Module 8 asks you to apply systematic tests such as flame tests for metal cations, precipitate reactions with specific reagents (Cl⁻, Ba²⁺, Ag⁺), and acid-base indicators. You should be able to follow a flowchart through multiple tests and justify each step based on expected reactions and observations.
Sample Flashcards
Q1: What are flame tests and what do they detect?
Flame tests identify metal ions by the characteristic colour they produce when heated in a Bunsen flame. Electrons are excited to higher energy levels and emit specific wavelengths of light as they return. Common colours: Li = red, Na = yellow, K = lilac, Ca = orange-red, Cu = green/blue, Ba = apple green.
Q2: How do precipitation reactions help identify ions?
Specific reagents are added to solutions to form characteristic insoluble precipitates, identifying the ions present. The colour and conditions of the precipitate help confirm identity. Solubility rules predict which combinations form precipitates.
Q3: How do you test for carbonate ions (CO₃²⁻)?
Add dilute acid (e.g. HCl) to the sample. If carbonate is present, it reacts with the acid to produce CO₂ gas (effervescence/bubbling). Confirm CO₂ by passing it through limewater — it turns milky (CaCO₃ precipitate forms).
Sample Quiz Questions
Q1: A yellow flame in a flame test indicates the presence of potassium ions.
Answer: FALSE
A yellow flame indicates SODIUM ions. Potassium produces a LILAC (pale purple) flame.
Q2: Adding silver nitrate to a solution containing chloride ions produces a white precipitate.
Answer: TRUE
AgNO₃ + Cl⁻ → AgCl↓ (white precipitate). This is a standard test for chloride ions.
Q3: The limewater test for CO₂ involves the solution turning milky due to CaCO₃ formation.
Answer: TRUE
CO₂ + Ca(OH)₂ → CaCO₃↓ + H₂O. The insoluble calcium carbonate precipitate makes the limewater appear milky/cloudy.
Related Concepts
Last updated: March 2026 · 3 flashcards · 3 quiz questions