Question

Balance the following equation by oxidation number method :

(i) K₂Cr₂O₇ + KCl + H₂SO₄ → KHSO₄ + CrO₂Cl₂ + H₂O

(ii) P + HNO₃ → H₃PO₄ + NO₂ + H₂O

(iii) CuO + NH₃ → Cu + N₂ + H₂O

(iv) Zn + HNO₃ →Zn(NO₃)₂ + NH₄NO₃ + H₂O

Answer 1

(i) K₂Cr₂O₇ + KCl + H₂SO₄ → KHSO₄ + CrO₂Cl₂ + H₂O

Step 5

To balance O and H atoms, HSO₄ is multiplied by 6, H₂O is multiplied by 3.

K₂Cr₂O₇ + 4KCl + 6H₂SO₄ → 2CrO₂Cl₂ + 6KHSO₄ + 3H₂O

(ii) P + HNO₃ → H₃PO₄ + NO₂ + H₂O

(iii) CuO + NH₃ → Cu + N₂ + H₂O

(iv) Zn + HNO₃ →Zn(NO₃)₂ + NH₄NO₃ + H₂O