Question

Give the chemical formula of the solution of borax in water.

Answer 1

Borax:

• Borax is a material made up of an element called Boron combined with Oxygen and soda.
• It is a soft, colorless, anhydrous, and decahydrate salt, as well as a pentahydrate salt, which are the most common forms of Borax.
• The chemical formula for Borax is (Sodium tetraborate decahydrate) is ${\mathrm{Na}}_2{\mathrm{B}}_4{\mathrm{O}}_7.10{\mathrm{H}}_2\mathrm{O}$.
• Borax can be naturally found in the evaporite deposits which are produced by the recurrent evaporation of seasonal lakes and this naturally occurring borax is purified by recrystallization.
• It is a component of cosmetics, and detergents, and is also used as a water softener and cleaning agent.

The solution of borax in water:

• Borax is a white crystalline solid which is less soluble in cold water but more soluble in hot water.
• The aqueous solution of Borax is alkaline, that is

$\underset{\mathrm{Borax}}{{\mathrm{Na}}_2{\mathrm{B}}_4{\mathrm{O}}_7\left(s\right)}+\underset{\mathrm{Water}}{7{\mathrm{H}}_2\mathrm{O}\left(\mathrm{l}\right)}\to \underset{\mathrm{Sodium}\mathrm{hydrooxide}}{2\mathrm{NaOH}\left(\mathrm{aq}\right)}+\underset{\mathrm{Boric}\mathrm{acid}}{4{\mathrm{H}}_2{\mathrm{BO}}_3\left(\mathrm{aq}\right)}$

• When Borax is dissolved in water, it ionizes the ${\mathrm{OH}}^{-}$(Hydroxyl ion) and by hydrolysis of the Borate ion Boric acid is produced.
• Boric acid is a mild acid and NaOH is a strong alkali, aqueous borax solutions are naturally alkaline.

Therefore, the chemical formula of the solution of borax in water is $\underset{\mathrm{Borax}}{{\mathrm{Na}}_2{\mathrm{B}}_4{\mathrm{O}}_7\left(s\right)}+\underset{\mathrm{Water}}{7{\mathrm{H}}_2\mathrm{O}\left(\mathrm{l}\right)}\to \underset{\mathrm{Sodium}\mathrm{hydrooxide}}{2\mathrm{NaOH}\left(\mathrm{aq}\right)}+\underset{\mathrm{Boric}\mathrm{acid}}{4{\mathrm{H}}_2{\mathrm{BO}}_3\left(\mathrm{aq}\right)}$.