This geography problem is solved step by step below, with detailed explanations to help you understand the method and arrive at the correct answer.
ScanSolve AI Answer
Step 1: Primary test for test tube A with dilute aqueous NaOH. White precipitate formed, insoluble in excess NaOH. Pb^2+ + 2OH^- Pb(OH)_2 No dissolution on adding excess NaOH. Inference: Pb^2+, Hg_2^2+, Bi^3+, Cu^2+, Cd^2+, Fe^3+, Al^3+, Cr^3+, Zn^2+ (but pattern matches group II). Step 2: Test with dilute aqueous NH_4OH. White precipitate, insoluble in excess. Pb(OH)_2 insoluble in NH_4OH Confirms group II cation. Step 3: Secondary test - H_2S in acidic medium. Black precipitate. Pb^2+ + H_2S PbS + 2H^+ Inference: Pb^2+. Cation in A: Pb^2+ Step 4: Primary test for test tube B with dilute aqueous NaOH. Blue precipitate formed, insoluble in excess NaOH. Cu^2+ + 2OH^- Cu(OH)_2 No dissolution on adding excess NaOH. Step 5: Test with dilute aqueous NH_4OH. Precipitate dissolves in excess to give deep blue solution. Cu(OH)_2 + 4NH_3 [Cu(NH_3)_4]^2+ + 2OH^- Inference: Cu^2+. Cation in B: Cu^2+ Step 6: Primary test for test tube C with dilute aqueous NaOH. Reddish-brown precipitate, insoluble in excess NaOH and NH_4OH. Fe^3+ + 3OH^- Fe(OH)_3 Insoluble in excess reagents. Step 7: Confirmatory test - potassium ferrocyanide. Prussian blue precipitate. 3K^+ + [Fe(CN)_6]^4- + Fe^3+ Fe_4[Fe(CN)_6]_3 Cation in C: Fe^3+ Step 8: Primary test for test tube D with dilute aqueous NaOH. White precipitate, soluble in excess NaOH. Zn^2+ + 2OH^- Zn(OH)_2 Zn(OH)_2 + 2OH^- [Zn(OH)_4]^2- Step 9: Test with aqueous NH_4OH. White precipitate dissolves in excess. Zn(OH)_2 + 4NH_3 [Zn(NH_3)_4]^2+ + 2OH^- Cation in D: Zn^2+ Final answers (Q11): A: Pb^2+ B: Cu^2+ C: Fe^3+ D: Zn^2+