Properties Of Borax

Properties Of Borax:

• Borax is a white crystalline solid, less soluble in water but more soluble in hot water.
• Borax dissolved in hot water to gives the alkaline solution of boric acid and sodium hydroxide.

                    Na₂B₄O₇  +  7H₂O  ———>  4H₃BO₃  +  2NaOH

• On heating, borax loses its water of crystallization and swells up to form a puff mass. On further heating, it melts into a clear liquid which solidified to a transparent glass like bead. Which consist of sodium metaborate and boric anhydride. This glass bead is commonly called as borax bead.                                                                                

                     Na₂B₄O₇.10H₂0 ———> Na₂B₄O₇ ———> 2Na₂BO₂ + B₂O₃

• Borax beads are used in laboratory to identify some metals in salts, through borax beads test. Nickel salts give brown colored bead. Cobalt slats give blue colored bead. White chromium salt gives green bead in flame.
• Borax reacts with acids like sulphuric acid and hydrochloric acid to form sparingly soluble boric acid.

                              Na₂B₄O₇ + 2HCl + 7H₂O  ———> 4H₃BO₃  +  2NaCl

                              Na₂B₄O₇  +  H₂SO₄  +  5H₂O  ———>  4H₃BO₃  +  2Na₂SO₄

• Borax reacts with Ammonium Chloride to form boron nitride.

                              Na₂B₄O₇  +  2NH₄Cl  ———>  2NaCl  +  2BN  +  B₂O₃  +  2H₂O

• Borax heated with ethyl alcohol and concentrated sulphuric acid, to forms vapors of triethylborane. When ignited these vapor burn with green edged flame.

                  Na₂B₄O₇  +  H₂SO₄  +  5H₂O ———> Na₂SO₄  +  4H₃BO₃

                  H₃BO₃  +  3C₂H₅OH  ———>  B(OC₂H₅)₃  +  3H₂O