NEET2026ChemistryChapterActual
During the qualitative analysis of salts using dilute acids, various gases are evolved which are identified by their specific confirmatory tests. Match the gases evolved in List I with their characteristic confirmatory tests in List II. List I (Gas Evolved) List II (Characteristic Test) A CO₂ 1 Turns acidified K₂Cr₂O₇ paper green B H₂S 2 Turns lead acetate paper black C SO₂ 3 Turns starch-iodide paper blue D NO₂ 4 Tu
Options
- AA-4, B-1, C-2, D-3
- BA-4, B-2, C-1, D-3
- CA-1, B-2, C-4, D-3
- DA-4, B-3, C-1, D-2
Correct answer
B. A-4, B-2, C-1, D-3
Step-by-step solution
A. CO₂ gas turns lime water milky due to the formation of insoluble calcium carbonate ( CaCO₃ ). Ca(OH)₂ + CO₂ CaCO₃ + H₂O Thus, A matches with 4. B. H₂S gas turns lead acetate paper black due to the formation of black lead sulfide ( PbS ). (CH₃COO)₂Pb + H₂S PbS + 2CH₃COOH Thus, B matches with 2. C. SO₂ gas turns acidified potassium dichromate ( K₂Cr₂O₇ ) paper green because it reduces Cr⁶⁺ (orange) to Cr³⁺ (green). K₂Cr₂O₇ + 3SO₂ + H₂SO₄ K₂SO₄ + Cr₂(SO₄)₃ + H₂O Thus, C matches with 1. D. NO₂ gas acts as an oxidizi