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HCL titration analysis

November 5, 2008


I need help with this, I have a 70 gals tank contain 30% HCl and DI water balance.I need to do a titration analysis to determine acid concentration to see how much acid addition I need for each week to maintain concentration. Can you show me how to do this type of calculation I am looking for titration data.

Thanks in advanced.

Calvin Nguyen
plating shop - Houston, Texas

First of two simultaneous responses -- November 8, 2008

Hi Calvin,

In order to do the analysis for free hydrochloric acid you need:

1) sodium hydroxide (approx. 1.0 N)
b) bromphenol indicator solution

This indicator is water soluble and exhibits a color change during the 3.0-4.6 pH interval going from yellow to purple.

First prepare the indicator solution by dissolving about 0.5 g of the bromphenol blue reagent in about 400 ml of distilled water to which about 3 ml of 0.1 N sodium hydroxide has been added. This neutralizes the sulfonic acid group thus making the indicator soluble.

Then, to a clean 250 Erlenmeyer flask, pipet 25.0 ml of the solution to be analyzed. Add about 60 ml of distilled water and about 1 ml of the bromphenol indicator. Titrate to the blue with standard sodium hydroxide.

=>> ml NaOH X N NaOH X 0.529 = oz/gal hydrochloric acid, (37%) <<==

Hope this helps.

Martin Michel
- Bielefeld, Germany

Second of two simultaneous responses -- November 10, 2008


You do not state what strength of Hydrochloric Acid you are using. From you statement, I would presume that you are using 30% by volume of a certain strength industrial hydrochloric acid and you wish to be able to analyze this so that you may maintain the concentration. Is this correct?

Gene Packman
process supplier - Great Neck, New York

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