Liquid caustic soda:

Sodium Hydroxide (Sodium Hydroxide) or Caustic Soda (Sodium Hydroxide) is a mineral compound with a NaOH formula that can be solid (percolum or granule) or solutions with different concentrations. Sodium hydroxide or caustic soda with saturated water is approximately 50% (by weight) (this saturation solution is known for the benefit of the liquid industry). Sodium hydroxide is an extremely open-burn metal that is soluble in water, methanol and ethanol. Sodium hydroxide, in solid or liquid state, absorbs high humidity and airborne carbon dioxide.