Wednesday, April 20, 2022

Identification test for boric acid

Learn the identification test for boric acid through a laboratory experiment or practical.

Aim:

To perform an identification test for boric acid.

Reference: Indian Pharmacopoeia (IP)

Requirements:

Glasswares and miscellaneous:
Test tube, measuring cylinder, pipette, glass rod, volumetric flask, beaker, dropper, rubber stopper, test tube stand, test tube holder, balance, etc.

Chemicals:
Boric acid (H3BO3), methanol (CH3OH), sulphuric acid (H2SO4), etc.

Theory of identification test for boric acid:

Identification tests are used to determine the drug's quality so that it can be used safely. Boric acid is often used as an antiseptic, insecticide, flame retardant, neutron absorber, or chemical precursor to other chemical compounds. It is also used as a dusting powder. 

It's a crystalline powder that's colorless or white, odorless, and has some bitter taste. It is sparingly soluble in water and ethanol, and freely soluble in boiling water, ethanol, and glycerin.

Procedure of identification tests for boric acid:

  1. With gentle warming, dissolve 0.1 gm of boric acid in 05 ml of methyl alcohol containing a few drops of H2SO4. Perform the flame test by igniting the solution. The flame has a green border because of the formation of methyl bromate.
  2. Taker 03 gm of boric acid and dissolve it in 90 ml of boiling water and cool. The solution is faintly acidic.
Identification test for boric acid

Observation table:

Sr.

Identification test

Observation

Inference

1

Dissolve 0.1 gm by warming+05 ml methanol+4-5 drops of H2SO4.

Flame test: Ignite the solution

Green flame

Boric acid:

Present/Absent

2

03 gm of sample+90 ml of water (boiling) and cool

Acid solution

Boric acid:

Present/Absent


Result:

The given sample is identified as boric acid.


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