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Is Barium Hydroxide Soluble in Water?

Barium hydroxide is an ionic molecule and is used as a strong base. It is a white crystalline powder. Barium hydroxide is slightly soluble in water. It gives one ion of Ba2+ and two ions of OH-1 upon dissolving in water. Read on to know more about the use of barium hydroxide and its properties!

What is Barium Hydroxide?

It is a strong base with the molecular formula, Ba(OH)2. It is a white odorless powder with poisonous nature. It is prepared by mixing barium oxide (BaO) or barium sulfide (BaS) in water.

Its boiling point is 780oC and its melting point is 78oC. The density and molecular weight of barium hydroxide are 3.74 g/cm3 and 171 g/mol respectively. The chemical equation for the preparation of barium hydroxide is given below

BaO + H2➞Ba(OH)2
BaS + H2O➞Ba(OH)2

Other names for barium hydroxide are caustic baryta and barium dihydroxide.

Structure of Barium Hydroxide


Reason for Solubility

As we know that barium hydroxide is a strong base but it is also slightly soluble in water. Most hydroxide salts are slightly soluble in water. The reason for this slight solubility is the lattice energy difference.

When we move down the group from Be to Ba then the size of the cation increases and lattice energy decreases. This decrease in lattice energy increases the solubility of salts from Be to Ba.

That is why Be(OH)2 is insoluble in water while Ba(OH)2 is slightly soluble in water.

Ba(OH)2O➞Ba2+ + 2OH-1

The solubility order of group II metal hydroxides is as follows


Be(OH)2 < Mg(OH)2 < Ca(OH)2 < Sr(OH)2 < Ba(OH)2

Properties of Barium Hydroxide

It has three covalent bonds in the structure. Barium hydroxide upon heating produces barium oxide at 800oC. It gives smooth titration using phenolphthalein indicators without titration errors.

It gives endothermic reactions. It is a strong base so it reacts with weak organic acids to produce various salts. It is corrosive.

Laboratory use of Barium Hydroxide

  • It is used in the titration of weak acids.
  • Barium hydroxide is mixed with sulphuric acid to prepare barium sulfate.
  • It is used in the organic synthesis of many organic compounds.
  • Barium hydroxide is used instead of sodium hydroxide and potassium hydroxide to give clear aqueous solutions (free of insoluble carbonates).
  • The barium hydroxide monohydrate is used for the dehydration of different compounds.
  • It is used in endothermic reactions.

Industrial Applications of Barium Hydroxide

  • It is a precursor in the preparation of various other barium salts i.e., BaO, BaCO3, etc.
  • Used as an additive in the petroleum industry.
  • It is used in the refining of sugar in the sugar industry.
  • Other industries that use barium hydroxide are the rubber industry, medicine, plastic industry, and ceramic industry.
  • It is used in the preparation of high-temperature superconductors.
  • Also used in the soap industry for fat saponification.
  • Barium hydroxide is used in the preparation of thermoplastics.
  • The barium hydroxide monohydrate is used as a drying agent.

Health Hazards of Barium Hydroxide

Barium hydroxide enters the environment through the mining and handling of barium compounds. It causes skin and eye irritation. It also causes skin burn. It may also cause a respiratory disease known as baritosis. Extreme inhalation of barium hydroxide affects the heart and central nervous system (CNS).


Barium hydroxide is an ionic hydroxide salt. It is prepared by dissolving the barium sulfate or barium oxide in water. It is slightly soluble in water. It ionizes to barium ions and hydroxide ions in water.

The slight solubility in water is due to the decrease in lattice energies of group II metal hydroxides. It is used in the laboratory for the titration of weak organic acids. It is also used in organic synthesis.

The titration with barium hydroxide uses the phenolphthalein indicator without any titration error. The aqueous solution of barium hydroxide is carbonate free so it is preferred in titrations instead of sodium hydroxide and potassium hydroxide. The inhalation of barium hydroxide causes baritosis (a respiratory disorder). It is poisonous.