А), б), г)
а) NaOH + HCl = NaCl + H₂O
Na⁺ + OH⁻ + H⁺ + Cl⁻ = Na⁺ + Cl⁻ + H₂O
OH⁻ + H⁺ = H₂O
б) 2 NaOH + CuSO₄ = Cu(OH)₂↓ + Na₂SO₄
2 Na⁺ + 2 OH⁻ + Cu²⁺ + SO₄²⁻ = Cu(OH)₂↓ + 2 Na⁺ + SO₄²⁻
2OH⁻ + Cu²⁺ = Cu(OH)₂↓
г) 6 NaOH + P₂O₅ = 2 Na₃PO₄ + 3 H₂O
6 Na⁺ + 6 OH⁻ + P₂O₅ = 6Na⁺ + 2 PO₄³⁻ + 3 H₂O
6OH⁻ + P₂O₅ = 3 H₂O + 2 PO₄³⁻