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### Topic: HF/HCl titration help  (Read 4716 times)

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#### etoh1

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##### HF/HCl titration help
« on: June 09, 2014, 11:29:36 AM »
I have a mixture of HF/HCl in solution. The concentration should be around 3% HF and 12% HCl. I need an accurate method for differentiating the two different acids. I have found one way that uses 1.6N NaOH to get total acidity. Once total acidity is calculated the HF is titrated with Thorium Nitrate (Th(NO3)4).

The math for this titration isn't making a lot of sense(this is exactly as it reads: Total acid = ((titrator Num x 1.6 div. 800) x 3646.1)/sample mass (~200 mg)
HF Concentration: ((Th(NO3)4 div 800) X 2000.64)/sample mass (mg))

Question 1.) Does anyone know a titration method for differentiating HF/HCl with out using Thorium nitrate?
Question 2.) If there's not another titration method for this what is the math for achieving total acidity? I know how to calculate normal acid-base titrations with one acid present in solution but have two is confusing.   Thank you

#### Hunter2

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##### Re: HF/HCl titration help
« Reply #1 on: June 10, 2014, 01:17:10 AM »
Why not titrate the Chloride from HCl with silvernitrate to avoid radioactive material. Flourides normally determinend with flourine sensitive electrodes, using Lanthannitrate.

#### Arkcon

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##### Re: HF/HCl titration help
« Reply #2 on: June 10, 2014, 09:40:43 AM »
Why not titrate the Chloride from HCl with silvernitrate to avoid radioactive material. Flourides normally determinend with flourine sensitive electrodes, using Lanthannitrate.

Silver fluoride is likewise insoluble.  The ion selective electrode for fluorine seems like a good idea.
Hey, I'm not judging.  I just like to shoot straight.  I'm a man of science.

#### Hunter2

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##### Re: HF/HCl titration help
« Reply #3 on: June 10, 2014, 09:51:22 AM »
Quote
Silver fluoride is likewise insoluble

Check the soloubility here:

http://en.wikipedia.org/wiki/Silver%28I%29_fluoride

#### Arkcon

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##### Re: HF/HCl titration help
« Reply #4 on: June 10, 2014, 01:02:22 PM »
Wow, way more soluble than I'd have expected another halide to be.
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#### etoh1

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##### Re: HF/HCl titration help
« Reply #5 on: June 16, 2014, 10:46:05 AM »
Originally I thought of using AgNO3 titration but given that silver(I) fluoride is fairly soluble I didn't think it would be beneficial. I still wouldn't know how to differentiate between the two halides. Thank you for the help.

#### Hunter2

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##### Re: HF/HCl titration help
« Reply #6 on: June 19, 2014, 01:02:33 AM »
Read again. Silverflouride has similar solubility like the silver nitrate.