April 20, 2024, 03:10:45 AM
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Topic: Experimental Design  (Read 581 times)

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Offline nightmarewing203

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Experimental Design
« on: February 21, 2024, 02:10:34 PM »
I was wondering if anyone could help for a question regarding experimental design.

One experiment requires you to design an apropiate experimental procedure for the determination of an 'old' bottle of phosphoric acid with an unknown concentration/purity.

In the description it states that 2 distinct experimental methods should be used. The confusing part is it says 1 should use volumetric titration and one should use pH titration but i thought these were the same thing. Normally I would just do a titration againts a standard of NaOH but what else could you use, a pH meter to measure the pH curve?
I would do this but we have never been tought this and it has never even been hinted at.
Apologies if my question seems trivial.

Offline Hunter2

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Re: Experimental Design
« Reply #1 on: February 21, 2024, 02:22:47 PM »
Instead of pH Meter an indicator can be used. Also phosphate can be analysed by using photometric or gravimetric  methods.

Offline Borek

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Re: Experimental Design
« Reply #2 on: February 21, 2024, 04:32:00 PM »
1 should use volumetric titration and one should use pH titration but i thought these were the same thing

Something is off here. Every titration is a volumetric method, so saying "volumetric titration" doesn't make much sense.

In general titration methods differ by a. reaction involved, b. method of end point detection. "volumetric titration" doesn't define either.

pH titration suggest detection of the end point, but it is not even clear if the reaction involved is related to the acid-base reaction typical for alkalimetry. Most likely it is, but I can imagine non acid-base reaction producing or consuming H+, so it can be possible to build a method around the idea.
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