Sciencemadness Discussion Board

KHSO4

joejoe - 14-1-2009 at 09:28

can anyone tell me where i can get KHSO4.

hissingnoise - 14-1-2009 at 12:17

I don't usually answer a question with another, but how many places have you tried so far?

woelen - 14-1-2009 at 12:39

You can make it from H2SO4 and K2CO3 (or KOH). Simply mix amounts at correct stoichiometry,

Jor - 14-1-2009 at 13:46

But you will lose a good amount of strong acid, wich is valuable, in the form of CO2. I always find it a waste. Also when I want to generate CO2 from NaHCO3, I use vinegar, and no hydrochloric acid. Maybe it's a mental thing, i just don;t like the idea of wasting something like HCl on plain CO2.

If I would want to make it, I would take make some profit out of the situation, and I would add conc. H2SO4 to a conc. KBr solution slowly, and after addition, let it cool. the crystals are relatively pure KHSO4, and you didn't waste your acid: you converted KBr in HBr (a valuable reagent), instead of turning carbonate in CO2.
Or ofcourse add KCl to conc. H2SO4, and bubble the gas (HCl) in water. You are left with KHSO4 and some hydrochloric acid.

However, for really pure KHSO4, react K2CO3 with H2SO4.

[Edited on 14-1-2009 by Jor]

kclo4 - 14-1-2009 at 16:46

Better to add H2SO4 to Na2SO4 to make it. Since you would be using half the acid.

You can buy it at most stores as sani-flush, or pH down for swimming pools. Read the ingredients in those.

not_important - 14-1-2009 at 16:59

Quote:

can anyone tell me where i can get KHSO4.


Better to add H2SO4 to Na2SO4 to make it. Since you would be using half the acid.


Hmmm ... a little nuclear chemistry there. But the idea is correct, if it is the potassium salt desired K2SO4 can be (or once could be) found as a fertiliser.

Another way is to fuse equimolar quantities of K2SO4 and (NH4)SO4, or two moles of (NH4)SO4 with one mole of K2CO3, or equmolar amounts of (NH4)2SO4 and KHCO3. The second hydrogen of H2SO4 is a fairly weak acid, and ammonium salts tend to decompose when heated; heating a mixture drives off the ammonia and in this case leaving KHSO4.

Ebao-lu - 15-1-2009 at 01:49

yes, just add H2SO4(any concentration) to K2SO4 in equimolar amounts and heat to remove water

Formatik - 15-1-2009 at 06:37

Also make sure to not heat too strongly. KHSO4 when heated in the molten state (Mp. 213.8° in an open vessel) only slowly releases its water and a part of it converts to K2S2O7. This conversion occurs more readily in a vacuum, heating at 230 to 350°C at pressure of 30-40 mmHg, H2O loss is 70%, and the mixture contains 68% K2S2O7. Above 400°, decomp. occurs forming H2SO4, SO2 and O2.

BlindedAchievement - 18-1-2009 at 18:24

http://www.citychemical.com/productdetails.asp?Pid=P7634

It is here where you will find your chemical.