June 20, 2021, 09:54:23 AM
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Topic: Lead(II) salt - white instead of black  (Read 318 times)

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Offline Enola

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Lead(II) salt - white instead of black
« on: May 02, 2021, 09:38:40 AM »
Hi. :)

I have a problem. I conducted a reaction in the laboratory: to Na2S(aq) I added CH3COOH (high concetration) and then Pb(CH3COO)2. But instead of black sediment I got white. And I'm not sure why. Any ideas?

Offline ACETAT

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Re: Lead(II) salt - white instead of black
« Reply #1 on: May 02, 2021, 11:55:29 AM »
Are you sure you added lead acetate and not zinc acetate?
Other possibility could be caused by the acetic acid, what happens if you  decrease the pH to much .

Offline Enola

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Re: Lead(II) salt - white instead of black
« Reply #2 on: May 02, 2021, 12:32:59 PM »
I'm absolutely sure.
The experiment was actually like this: in the test tube no 1 put egg white, add 30% NaOH, then add CH3COOH (high concetration) and Pb(CH3COO)2 - here I got black sediment.
In the test tube no 2 put Na2S(aq), add CH3COOH (high concetration) and then Pb(CH3COO)2 - here I got white sediment.

My friend did the same experiment and she got the same results.

Offline Borek

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Re: Lead(II) salt - white instead of black
« Reply #3 on: May 02, 2021, 12:51:37 PM »
to Na2S(aq) I added CH3COOH (high concetration)

It should stink as hell. Did it?

My bet is what you were given as Na2S was actually not sulfide. Sulfate perhaps? That would fit the white color of the precipitate.
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Offline Enola

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Re: Lead(II) salt - white instead of black
« Reply #4 on: May 02, 2021, 01:13:39 PM »
to Na2S(aq) I added CH3COOH (high concetration)

It should stink as hell. Did it?


Not at all - that also surprised me.

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