Can palmitic acid be titrated by sodium hydroxide?

I am currently researching ideas for my IB Chemistry Internal Assessment and the research question that I currently have is:

Does dilution affect the concentration of palmitic acid in Eskinol Facial Wash?

I'm concerned that the experiment may not work if the concentration of the palmitic acid cannot be found in the first place, which would mean that I get no data.

1 Answer
Apr 28, 2018

Here's what I find.

Explanation:

(a) Titration of palmitic acid

Yes, you can titrate palmitic acid with #"NaOH"#, but not in water.

Palmitic acid is insoluble in water (0.04 mg/mL) but soluble in ethanol and isopropyl alcohol.

You could titrate a solution of the palmitic acid in isopropyl alcohol with aqueous #"NaOH"# to a thymol blue endpoint (pH 9.8).

(b) Does dilution affect the concentration of palmitic acid?

Yes! That is the whole point of dilution.

(c) A practical question

Here is a label for the product.

3.bp.blogspot.com

The ingredient list also includes lauric, myristic, and stearic acids.

How do you plan to titrate just the palmitic acid?