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Topic: Why does PbO2 turn dark brown when HNO3 is added?  (Read 6754 times)

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Offline Timothy

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Why does PbO2 turn dark brown when HNO3 is added?
« on: February 18, 2010, 02:44:49 PM »
Why does a light brown powder of PbO2 made from reacting Pb(OH)2 and NaOCl turn dark brown when HNO3 is added? Any help will be greatly appreciated.

Offline BluRay

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Re: Why does PbO2 turn dark brown when HNO3 is added?
« Reply #1 on: February 18, 2010, 03:27:38 PM »
Don't really know, maybe the one got with the previous reaction still contains some Pb(OH)2 which is then dissolved with HNO3 (and oxidized to PbO2) leaving the darker PbO2 alone (or, however, in greater concentration) in the solid phase, which is much darker.

Offline Timothy

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Re: Why does PbO2 turn dark brown when HNO3 is added?
« Reply #2 on: February 18, 2010, 03:46:05 PM »
Thanks, that sounds like a reasonable answer.

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