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Topic: Issue with Fajans titration  (Read 893 times)

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Offline Hasanlabash

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Issue with Fajans titration
« on: September 22, 2019, 04:29:39 PM »
Last week we did the Fajans titration at school, but we used HCl solution as analyte instead of some other source of chloride like NaCl.
We prepared two HCl-analytes, one neutralized and one still acidic. We then titrated each analyte separately with a solution of silver nitrate.
The titration of the neutralized HCl solution went smoothly and we got normal results, i.e. white AgCl precipitated out. But the titration with the acidic HCl solution didn't work out at all; it took way too much AgNO3 and we got an Ag precipitate instead of AgCl and the solution took on a bluish colour.
Our teacher wants us to figure out why this happened, but I have no idea since HCl is an oxidation agent and the Ag+ ions in the solution need to be reduced to become metallic Ag.

Any help is appreciated
« Last Edit: September 22, 2019, 05:47:15 PM by Hasanlabash »

Offline Borek

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Re: Issue with Fajans titration
« Reply #1 on: September 22, 2019, 04:44:17 PM »
Metallic Ag that later precipitated as AgCl? Blue? Doesn't sound OK.

Can you just list your observations, without guessing what have happened?
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