Among the following, the number of reactions that evolve dioxygen (O₂) gas as one of the products is :
(1) KO₂ + H₂O →
(2) H₂O₂ + KMnO₄ (acidic) →
(3) F₂ + H₂O →
(4) HOCl + H₂O₂ →
(5) Na₂O₂(s) + CO₂ →
(6) Pb₃O₄ + dil. HNO₃ →
(7) (NH₄)₂Cr₂O₇ $Δ$

Question

Among the following, the number of reactions that evolve dioxygen (O₂) gas as one of the products is :

(1) KO₂ + H₂O →

(2) H₂O₂ + KMnO₄ (acidic) →

(3) F₂ + H₂O →

(4) HOCl + H₂O₂ →

(5) Na₂O₂(s) + CO₂ →

(6) Pb₃O₄ + dil. HNO₃ →

(7) (NH₄)₂Cr₂O₇ $Δ$

TestHub · Accepted Answer

O₂ evolved in (1), (2), (3), (4), (5) = 5. (6) gives Pb(NO₃)₂ + PbO₂ + H₂O (no O₂) and (7) gives Cr₂O₃ + N₂ + H₂O.

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