2-4

1) H₂O + P₂O₅ = 2HPO₃

2) B₂O₃ + 3H₂O = 2H₃BO₃

3) Na₂O + H₂O = 2NaOH

4) P₂O₅ + 3H₂O = 2H₃PO₄

2-5

а) Fe + CuCl₂ = Cu + FeCl₂

3Zn + 2FeBr₃ = 3ZnBr₂ + 2Fe

3HgCl₂ + 2Al = 2AlCl₃ + 3Hg

Mg + 2H₂O = H₂ + Mg(OH)₂

б) Fe₂O₃ + 3H₂ = 3H₂O + 2Fe

3PbO + 2Al = Al₂O₃ + 3Pb

Cr₂O₃ + 3Mg = 3MgO + 2Cr

2Al + 6H₂O = 2Al(OH)₃ + 3H₂

2-6

а) 2KCIO₃ = 2KCI + 3O₂

2NaNO₃ = 2NaNO₂ + O₂

2CuOH = Cu₂O + H₂O

2Al(OH)₃ = Al₂O₃ + 3H₂O

б) 3KCIO = KCIO₃ + 2KCI

NH₄NO₃ = N₂O + 2H₂O

NH₄NO₂ = N₂ + 2H₂O

(CuOH)₂CO₃ = 2CuO + H₂O + CO₂

2-7

а) Mg + 2HCI = H₂ + MgCl₂

4HJ + O₂ = 2J₂ + 2H₂O

10Al + 3V₂O₅ = 5Al₂O₃ + 6V

Br₂ + 2KJ = 2KBr + J₂

б) 6HCI + 2Al = 2AlCl₃ + 3H₂

2Al + WO₃ = W + Al₂O₃

J₂ + H₂S = S + 2HJ

2F₂ + 2H₂O = 4HF + O₂