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Specialty Chemistry Forums => Other Sciences Question Forum => Topic started by: elisa on April 14, 2015, 05:32:48 AM

Title: Potassium phosphite formulation
Post by: elisa on April 14, 2015, 05:32:48 AM
Hello everyone,
I have a problem with potassium phosphite commercial formulation. Usually, the label of these products indicates:
30 % P2O5
20 % K2O
They are obtained by dissolution of phosphorous acid in water and potassium hydroxide:
H3PO3 + KOH —> KH2PO3 + H2O
KH2PO3 + KOH —> K2HPO3 + H2O
I would like to find the initial concentration of H3PO3 used to obtain the concentration reporte in the label C of the commercial products. I think that:
in P2O5 the percentage of elemental P is 43.64 %, so starting from a solution 30 % P2O5 the real concentration of elemental P is 13.09 %.
In H3PO3 the percentage in weight of P is 37.77% so, starting from 13.09% I will obtain 34.66% H3PO3.
Is it right for you? Thank you for your answers,
Elisa