Lye

Caustic Potash: KOH

Ca(OH)₂(aq) + K₂CO₃(aq) = CaCO₃(s) + 2 KOH(aq)

Caustic Soda: NaOH

Ca(OH)₂(aq) + Na₂CO₃(aq) = CaCO₃(s) + 2 NaOH(aq)