Wednesday, September 30, 2020

Properties Of Boric Acid

                Boric acid reacts with sodium hydroxide to form sodium metaborate and sodium tetraborate. 

                   H3BO3  +  NaOH  ———>  NaBO2  +  2H2O

                  4H3BO3  +  2NaOH  ———>  Na2B4O7  +  7H20

Action Of Heat:

              Boric acid heated above 170 degree Celsius to gives metaboric acid.

                                 4H3BO3  ———>  4HBO2  +  H20

              Boric acid heated above 300 degree Celsius to gives tetraboric acid.

                               4HBO2   ———>  H2B4O7  +  H2O

             Tetraboric acid heated above 330 degree celsius to gives boron trioxide.

                               H2B4O7  ———>  2B2O3  +  H2O

Action Of Ethyl Alcohol:

              Boric acid reacts with ethyl alcohol in the presence of concentrated sulphuric acid to form triethylborate. The ethyl borate burns with green edged flame.

                              4H3BO3  +  3C2H5OH   ———>   B(OC2H5)3  +  3H2O

Action Of Calcium Fluoride:

            Boric acid reacts with calcium fluoride in the presence of concentrated sulphuric acid to gives boron trifluoride.

                            2H3BO3  +  3CaF2  +  3H2SO4   ———>  2BF3  +  3CaSO4  +  6H2O

Tuesday, September 29, 2020

Preparation Of Boric Acid

 Boric Acid:

             A mixture of concentrated sulphuric acid reacts with borax to form boric acid.

Na2B4O7  +  H2SO4  +  5H2O ———>      Na2So4          +          4H3BO3

                                                          ( Sodium sulfate )        ( Boric acid ) 

Boric acid can be extracted from colemanite. 

Ca2B6O11  +  11H2O4  +  SO2  ———>  Ca(HSO3)2  +  6H3BO3

Tuesday, September 22, 2020

Uses Of Boric Acid

  • Boric acid is used in the manufacture of pottery glaze glass, enamels and pigments.
  • Boric acid is used as an antiseptic, insecticide and flame retardants.
  • Boric acid is used as a food preservatives.
  • Boric acid is used in the production of LCD flat panel display.
  • Boric acid is used to prevent existing wet and rot in timber etc....

Thursday, September 10, 2020

Uses Of Borax

 Borax Uses:

  • Borax is used fir the identification of colored metal ions.
  • Peroxoborate present in washing powder. It's a cleaning and bleaching agent.
  • Borax is a flux for soldering. And also acts as a good preservative.
  • In the manufacture optical and borosilicate glass, enamels and glazes for pottery.
  • Borax is used as fungicide, fire retardant and in softening water.
  • Borax is used for stiffening agent for candle wicks. 
  • Borax is used as antiseptic soaps.

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

Borax Preparation

 Borax  [Na2B4O7.10H2O]              

          Borax is a sodium salt of tetraboric acid. Fine powdered colemanite ( Ca2B6O11 ).    Is boiled with sodium carbonate ( washing soda ) solution. The insoluble calcium carbonate is filtered off ( CaCO3 ).  Then it is concentrated and cooled to get the crystals of borax. The sodium metaborate is treated with           CO2  gas which converts into borax.

Ca2B6O11  +  2Na2CO3  ———>  Na2B4O7     +      2NaBO2         +        2CaCO3

Colemanite                                  Borax                 Sodium                     calcium

                                                                            metaborate                carbonate

2NaBO2  +  CO2  ———>  Na2B4O7  +  Na2CO3

Wednesday, September 9, 2020

Uses Of Boron

 Boron Uses:

  • The compound of boron are boric acid, borax and boric oxide. These can be found in eye drops, mild antiseptics, washing powders and title glazes. Borax used to make bleach and food preservative.
  • Amorphous boron is used as a rocket fuel igniter.
  • In the manufacture of pyrex glass, boric acid is used
  • Sodium octaborate is a flame retardant.
  • Boron is essential for the cell walls of plants.
  • Boron has the capacity to absorb neutrons. This means the isotope of Boron-10 used to regulate nuclear reactors.