Comprehensive Lesson Plan on Qualitative Analysis for SS3 Chemistry

Fill-in-the-Blank Questions with Options (A, B, C, or D)

1. When NaOH(aq) is added to a solution containing Zn²⁺, a __________ precipitate forms, which is soluble in excess NaOH.
   a) Blue
   b) Green
   c) White
   d) Reddish-brown
2. The cation that forms a reddish-brown precipitate with NaOH(aq) is __________.
   a) Fe²⁺
   b) Fe³⁺
   c) Cu²⁺
   d) NH₄⁺
3. A cation that forms a blue precipitate with NaOH(aq) is __________.
   a) Cu²⁺
   b) Fe³⁺
   c) NH₄⁺
   d) Al³⁺
4. The test for NH₄⁺ involves the evolution of a __________ gas with an irritating smell that turns moist red litmus paper blue.
   a) Greenish-yellow
   b) Colourless
   c) Reddish-brown
   d) Pungent
5. The confirmatory test for Cl⁻ involves adding dilute HNO₃ followed by __________.
   a) BaCl₂
   b) AgNO₃
   c) FeSO₄
   d) NaOH
6. The ion that gives a brown ring when freshly prepared FeSO₄ and concentrated H₂SO₄ are added is __________.
   a) SO₄²⁻
   b) NO₃⁻
   c) CO₃²⁻
   d) SO₃²⁻
7. To test for SO₄²⁻, add dilute HCl followed by __________.
   a) BaCl₂
   b) NaOH
   c) NH₃
   d) AgNO₃
8. The gas that turns limewater milky during the test for carbonates is __________.
   a) NH₃
   b) CO₂
   c) SO₂
   d) NO₂
9. The test solution changes acidified KMnO₄ solution from purple to colourless if it contains __________.
   a) CO₃²⁻
   b) SO₃²⁻
   c) NO₃⁻
   d) Cl⁻
10. The gas that rekindles a glowing splint is __________.
    a) Hydrogen
    b) Chlorine
    c) Oxygen
    d) Ammonia
11. A green residue turning black upon heating indicates the presence of __________.
    a) Fe³⁺
    b) Fe²⁺
    c) Cu²⁺
    d) Zn²⁺
12. The cation confirmed by a deep blue solution when excess NH₃ is added is __________.
    a) NH₄⁺
    b) Cu²⁺
    c) Al³⁺
    d) Pb²⁺
13. The gas that gives a pop sound when ignited is __________.
    a) Chlorine
    b) Hydrogen
    c) Oxygen
    d) Nitrogen
14. Acidified K₂Cr₂O₇ turning green confirms the presence of __________ gas.
    a) NO₂
    b) SO₂
    c) H₂
    d) CO₂
15. A pungent greenish-yellow gas that bleaches litmus paper is __________.
    a) Chlorine
    b) Ammonia
    c) Sulphur dioxide
    d) Hydrogen chloride

Qualitative Analysis

1. What cation forms a white precipitate with NaOH, soluble in excess?
   Zn²⁺, Al³⁺, and Pb²⁺.
2. How can NH₄⁺ be identified?
   By adding NaOH(aq) and warming, it evolves a gas that turns moist red litmus paper blue.
3. What does a brown ring test confirm?
   The presence of NO₃⁻ ions.
4. How is SO₄²⁻ confirmed?
   By adding BaCl₂ followed by dilute HCl, resulting in a white precipitate insoluble in HCl.
5. What gas turns limewater milky?
   Carbon dioxide (CO₂).
6. Which gas rekindles a glowing splint?
   Oxygen (O₂).
7. What is the test for Cu²⁺ using NH₃(aq)?
   It forms a pale blue precipitate, which dissolves in excess NH₃(aq) to give a deep blue solution.
8. How can Cl⁻ be identified?
   Add dilute HNO₃ followed by AgNO₃; a white precipitate forms, dissolving in excess NH₃.
9. What is the result of heating Fe²⁺ residue?
   It turns from green to black.
10. How can CO₃²⁻ and SO₃²⁻ be differentiated?
    Use MgSO₄; CO₃²⁻ forms a white precipitate, while SO₃²⁻ does not.
11. What confirms HCl gas?
    It forms white fumes with NH₃ gas.
12. What gas has a pungent smell and bleaches litmus paper?
    Chlorine (Cl₂).
13. How is SO₂ confirmed?
    It turns acidified KMnO₄ from purple to colourless.
14. What gas produces a pop sound on ignition?
    Hydrogen (H₂).
15. Which gas turns starch-iodide paper blue-black?
    Nitrogen dioxide (NO₂).

Evaluation Questions

1. Describe the confirmatory test for NH₄⁺ ions.
2. What is observed when BaCl₂ and HCl are added to SO₄²⁻?
3. How is CO₂ gas identified in a reaction?
4. State the color change observed when Fe²⁺ is heated strongly.
5. Which ion gives a deep blue solution with excess NH₃?
6. Write the test used to confirm Cl⁻ ions.
7. What gas turns acidified KMnO₄ from purple to colourless?
8. How is the presence of NO₃⁻ confirmed?
9. Which gas gives a pop sound when ignited?
10. Differentiate between the confirmatory tests for SO₃²⁻ and CO₃²⁻.