In Clarke’s process, the salts responsible for hardness get precipitated as
MgCO3, CaOH2
MgOH2, CaOH2
MgOH2, CaCO3
MgCO3, CaCO3
CaHCO32 and MgHCO32are responsible for temperorary hardness of water which are removed in Clarke's process;
CaHCO32+ CaOH2 → CaCO3↓+H2O+CO2
MgHCO32+ 2CaOH2 → CaCO3↓+MgOH2↓+H2O+CO2
Ksp of MgOH2 < Ksp of MgCO3 ∴ MgOH2 is precipitated but not MgCO3