Balance the following chemical reactions.(i) K2Cr2O7 + KI + H2SO4 → K2SO4 + Cr2(SO4)3 + H2O + I2(ii) K2Cr2O7 + H2SO4 + H2S → K2SO4 + Cr2(SO4)3 + H2O + 3S

Q.10 Balance the following chemical reactions.
(i) K₂Cr₂O₇ + KI + H₂SO₄ → K₂SO₄ + Cr₂(SO₄)₃ + H₂O + I₂
(ii) K₂Cr₂O₇ + H₂SO₄ + H₂S → K₂SO₄ + Cr₂(SO₄)₃ + H₂O + 3S

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(i) K₂Cr₂O₇ + 6KI + 7H₂SO₄ → 4K₂SO₄ + Cr₂(SO₄)₃ + 7H₂O + 3I₂

Cr changes from +6 to +3 (gain of 3e^– per Cr, 6e^– per Cr₂O₇^2–); I changes from –1 to 0, so 6 I^– are needed, giving 3I₂. Balancing K (8), S (7) and then H and O gives the coefficients above.

(ii) K₂Cr₂O₇ + 4H₂SO₄ + 3H₂S → K₂SO₄ + Cr₂(SO₄)₃ + 7H₂O + 3S

Dichromate gains 6e^–; each H₂S loses 2e^– (S: –2 → 0), so 3H₂S are needed. Check: H 8 + 6 = 14 = 2 × 7; S 4 + 3 = 7 = 1 + 3 + 3; O 7 + 16 = 23 = 4 + 12 + 7.

Doubtly AI · 28 Oct 2026 AI-verified · Oct 2026 Report

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Balance the following chemical reactions.(i) K2Cr2O7 + KI + H2SO4 → K2SO4 + Cr2(SO4)3 + H2O + I2(ii) K2Cr2O7 + H2SO4 + H2S → K2SO4 + Cr2(SO4)3 + H2O + 3S

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