1) 2BiCl₃+3H₂S=Bi₂S₃↓+6HCl
2Bi ⁺³ + 6Cl⁻+ 6H⁺+3S²⁻ = Bi₂S₃↓+ 6H⁺ + 6Cl⁻
2Bi ⁺³ + 3S²⁻=Bi₂S₃↓
2) MgOHCl+HCl=MgCl₂+H₂O
MgOH⁻ + Cl⁻+ H⁺+ Cl⁻ = Mg²⁺ + 2Cl⁻+H₂O
MgOH⁻ + H⁺ = Mg²⁺+H₂O
3) Fe(NO₃)₃+3KOH=Fe(OH)₃↓+3KNO₃
Fe⁺³ +3NO₃⁻+3K⁺ +3OH⁻=Fe(OH)₃↓+3K⁺ +3NO₃⁻
Fe⁺³ +3OH⁻=Fe(OH)₃↓