Determination of Free Acidity as Hydrochloric Acid in Ferric Chloride Solution RDM-5003

December 11, 2009
RD Chemical Company in Chemical Milling, Process

Determination of Free Acidity as Hydrochloric Acid in Ferric Chloride Solution (RDM-5003)

Procedure for Analysis

Theory:
Ferric iron is complexed with Potassium Fluoride to prevent hydrolysis. The free acid is then titrated with standard Sodium Hydroxide to the Phenolphthalein end point.

Reagents Required:

• Phenolphthalein
• Sodium Hydroxide (NaOH) standard 0.10N solution.
• 33% Potassium Fluoride, neutralized to Phenolphthalein endpoint.

Procedure:

• 1. In 150 ml beaker, weigh accurately 1-2 grams of ferric chloride solution. Add 50 ml of distilled water.
• 2. Add 25 ml of Potassium Fluoride solution and mix.
• 3. Add few drops Phenolphthalein indicator
• 4. Titrate with 0.1N NaOH to first permanent trace of pink

Calculation:
% Free acidity as HCl = mls 0.1N NaOH x 0.365 grams of sample

Article originally appeared on RD Chemical Company - Manufacturing Chemists (http://rdchem.com/).