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Talk:Phosphoric acid/Archives/2021

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Boiling point

While the water evaporates, the acid does not. After reaching 100 % it keeps boiling due to condensation of H3PO4 to things like Oligophosphoric and polyphosphoric acids. The acid itself does not really boil. I will correct this in the article accordingly.

This paper has a Temperature-Composition Diagram for the System P2O5<->H2O. At 270 °C the vapour reaches just 0,1 % P2O5 content. 85 % H3PO4 in the vapor are reached at 61.5 % P2O5 and thus at about 800 °C


Temp. Of boiling acid, °C P4O10 in vapor, wt. %
221-228 0.009
228-234 0.014
234-241 0.02
241-250 0.03
250 0.02
250-259 0.05
259-268 0.08
268-273 0.12
273-281 0.16
281-290 0.29
290-301 0.47
301-308 0.64
308-316 0.89
320 1.2
350-362 1.62
362-385 1.96
410 6.1
350 1.93
400 5.1
449 9.5
548 20.3
647 35.2
696 39.1
744 47.8
793 60.2
840 65.1

--Eheran (talk) 09:48, 25 February 2021 (UTC)