Author Topic: KH2PO3 reactions  (Read 8081 times)

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  • Guest
KH2PO3 reactions
« on: June 13, 2003, 09:11:00 PM »
Swix is able to obtain 600g/L solution of KH2PO3 and K2HPO3 with seemingly nothing else there.

The reactions of how these are produced are as follows:
H3PO3 + KOH -> KH2PO3 + H2O
KH2PO3 + KOH -> K2HPO3 + H20

Now to reverse these reactions and obtain aquase solution of H3PO3 what would the reactions look like?

K2HPO3 + H2SO4 -> H3PO3 + K2SO4
KH2PO3 + H2SO4 -> H3PO3 + KHSO4

Is this correct?


  • Guest
"KH2PO3 reactions"
« Reply #1 on: June 13, 2003, 10:13:00 PM »
hello again x.
Have you ever considered an ion-exchange resin to remove 1xpottasium and replace with 1xhydrogen. quite simple and works well with other exchanges swibn has done. 8)


  • Guest
Swix has heard about the ion exchange resin,...
« Reply #2 on: June 14, 2003, 01:24:00 AM »
Swix has heard about the ion exchange resin, but Swix has no idea what it is. What is it? Can you buy it cheaply?

Swix has just added 10mL of H2SO4 to 100mL of 20% solution of K2HPO3 and KH2PO3. A white precipitate was noted that appeared to be of crystaline nature resembling frosty stars. The precipitate was seemingly redisolving. 50mL of MeOH was added. This crashed out a thick white mess. There were bubble evolving.

What happened? What's the gas? The idea was to convert the phosphite into phosphorous acid. Then add MeOH so H3PO3 can go into it. And add enough MgSO4 to push the acid into MeOH since MgSO4 is more soluable in water than H3PO3.

Any ideas? My first idea is that its K2SO4 crashing out of the super saturated solution because due to my calculations there should be about 10g of K2SO4 formed more than 100mL of water can hold. The gas could have been simply air bubbles.