Borax may be a compound and Sodium borate, sodium tetraborate, or disodium tetraborate are other names of it. It’s a crucial boron compound, a mineral, and a salt of boric acid. It’s a soft, colourless compound of Boron and dissolvable in water. Moreover, the essential use of it is in laundry and other cleaning products. During this article, we’ll discuss the concept of the borax formula, its preparation, and solved examples.
Sodium tetraborate decahydrate is the IUPAC name of borax. It’s a component of the many detergents, cosmetics. The utilization of it includes buffers solutions in biochemistry. Within the manufacture of fibreglass, it’s used as a flux in metallurgy, neutron-capture shields for radioactive sources. Texturing agent in cooking, as a cross-linking agent in slime, is another use of it.
- Molecular Formula – H20B4Na2O17
- Simplified chemical formula – Na₂[B₄O₅(OH)₄]·8H₂O
The term borax is usually used for several closely related minerals or chemical compounds. It differs in their crystal water content. Different borax found is anhydrous sodium tetraborate(Na2B4O7), sodium tetraborate pentahydrate (Na2B4O7·5H2O). Equivalently the octahydrate, (Na2B4O5(OH)4·8H2O) is that the same.
We also find it in deposits due to the evaporation of seasonal lakes. Present borax is purified by recrystallization. We can synthesise borax from boron compounds.
From the chemical perspective, the borax contains the [B4O5(OH)4]2− ion. Conversion of borax to boric acid and other borates can occur easily. This process was first used by Wilhelm Homberg. Borax reacts with an acid to supply boric acid. Its reaction with acid to make boric acid is:
Na2B4O7·10H2O + 2 HCl → 4 B(OH)3 + 2 NaCl + 5H2O
Preparation of Borax
The use of tincal is often useful within the preparation of borax. Tincal or suhaga are present in borax. Tincal is boiled with water and it filters and removes impurities of sand, clay. The concentration of filtrate occurs until crystallization begins then the cooling procedure starts. The concentration of filtrate occurs when crystals of the borax filter.
From colemanite (Ca2B6O11):
Ca2B6O11 + 2Na2CO3 → Heat→ Na2B4O7 + 2NaBO2 + 2CaCO3↓
4NaBO2 + CO2 → Na2B4O7 + Na2CO3
We then treat the borax and sodium metaborate of the remaining solution with CO2 to convert sodium metaborate to borax. The solution is then concentrated and cooled to crystallize borax.
From boric acid: It is ready from boric acid by boiling with sodium carbonate. On cooling the solution, borax separates out.
4H3BO3 + Na2CO3 →Na2B4O7 + 6H2O +CO2 ↑
Solved Examples for Borax Formula
Q1] Write the reactions of the solution of borax because of hydrolysis.
Solution – The reactions are as follows,
Na2B4O7 + 2H2O -→ 2NaOH + H2B4O7
H2B4O7 + 5H2O → 4H3BO3
Q2] Write the reaction on adding the calculated quantity of Conc.sulphuric acid to a hot concentrated solution of borax, for the formation of boric acid.
Solution – The two reactions are,
Na2B4O7 + H2SO4 → Na2SO4 + H2B4O7
H2B4O7 + 5H2O → 4H3BO3
Q 3] Tell what is going to happen when on heating borax with ethyl alcohol and concentrated vitriol and write a reaction.
Solution – When it is heated with ethyl alcohol and vitriol, it produces vapors of trimethyl borate. When ignited these vapors burn with green edged flame, the subsequent reaction occurs;
Na2B4O7 + H2SO4 + 5H2O → Na2SO4 + 4H3BO3
H3BO3 + 3C2H5OH → B(OC2H5)3 + 3H2O