Model Question Paper — 2 — Question 1

(i) Carbon dioxide gas has no effect on acidified potassium permanganate (KMnO₄) and acidified potassium dichromate (K₂Cr₂O₇) solution whereas sulphur dioxide gas turns acidified potassium permanganate from pink to clear colourless and acidified potassium dichromate from orange to clear green.

2KMnO₄ + 2H₂O + 5SO₂ ⟶ K₂SO₄ + 2MnSO₄ + 2H₂SO₄

K₂Cr₂O₇ + H₂SO₄ + 3SO₂ ⟶ K₂SO₄ + Cr₂(SO₄)₃ + H₂O

(ii) Hydrogen gas burns with a 'pop' sound in air whereas hydrogen chloride forms a curdy white ppt. on passage through AgNO₃ solution. The precipitate dissolves in excess of NH₄OH.