Purpose and Preparation
The purpose of performing an assay is to determine the percentage of purity of a given amount of the boric acid. To perform the assay, the equipment you will need includes a burette (approximately 50ml), a 10ml volumetric pipette, 100ml volumetric flask, 250ml conical flask, a weighing bottle and a scale. Chemicals required include boric acid, KHP, 0.1M sodium hydroxide, glycerin and phenolphthalein.
To begin the experiment, weigh out a specified amount of boric acid and add equal parts of water and glycerol while dissolving into solution. Next, add a few drops of phenophthalein, which acts as an indicator for the titration. Once added, begin titrating with sodium hydroxide until the solution takes on and maintains a pink color. For the results to be more accurate, repeat the titration three times, which provides more confidence in the data. To compare the boric acid to a standard, complete a titration on a solution containing just glycerol and water. This can be used to calculate the percent purity of the boric acid solution.
Theory of the Assay
Boric acid is a weak acid that must be combined with a polyhydroxy compound, in this case glycerin, for a titration assay to be performed. Once combined, it can be titrated against a strong base like sodium hydroxide, which causes the indicator to change colors. This is because the glycerin esterfies the boric acid to produce a complex that behaves like an acid, which in turn allows the titration to be carried out.
Boric Acid Safety
Boric acid is a chemical substance that is also known as orthoboric acid or sassolite. It is used as an ingredient in...
Borax Vs. Boric Acid
Though borax and boric acid come from the same element, boron, they have different properties and different uses in the home.
Titration of Sodium Carbonate With Hydrochloric Acid
Sodium carbonate is a basic compound, meaning that it generates hydroxide ions (OH?) when dissolved in water. Hydrochloric acid is acidic, meaning...
How to Insert a Rectal Suppository
For millions of people, medical problems such as an impacted colon require the insertion of a rectal suppository. While not difficult, this...
Boric Acid Powder Uses for a Dog's Bath
Boric acid has been used as an antifungal, antiseptic and an insecticide These applications also can be used on animals, such as...