Potassium hydrogen carbonate acidic, basic or neutral salt? (1 Viewer)
- Thread starter enigma_1
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kev-kun
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Hopefully explains it ^^
Poor explanation. What's with the hydrates? Shouldn't even be talking about that if we're looking at an aqueous reaction.
someth1ng
Retired Nov '14
Just this should suffice. kev-kun's explanation is poor because it doesn't explain why it isn't acidic, that is, why it's not acidic because it can donate protons.
theprofitable95
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KHCO3 can dissociate into K+ and HCO3-. K+ is a neutral ion. HCO3 exists in two different equilibrium
H2CO3 + H20 <-> HCO3- + H3O+ (first ionisation of carbonic acid)
HCO3- + H20 <-> CO3 2- + H3o+ (second ionisation)
The equilibrium of the second ionisation lies very far to the left, so HCO3 does not have much of a tendency to donate protons, and is thus not acidic in solution. H2CO3 is a weak acid, and equilbrium also lies to the left (as someone earlier mentioned). Hence HCO3 has more of a tendency to accept electrons, and is hence BASIC in solution. However, HCO3 is actually an amphiprotic substance (and should always be referred to as such), but it is basic in solution for the reasons above.
H2CO3 + H20 <-> HCO3- + H3O+ (first ionisation of carbonic acid)
HCO3- + H20 <-> CO3 2- + H3o+ (second ionisation)
The equilibrium of the second ionisation lies very far to the left, so HCO3 does not have much of a tendency to donate protons, and is thus not acidic in solution. H2CO3 is a weak acid, and equilbrium also lies to the left (as someone earlier mentioned). Hence HCO3 has more of a tendency to accept electrons, and is hence BASIC in solution. However, HCO3 is actually an amphiprotic substance (and should always be referred to as such), but it is basic in solution for the reasons above.
How do you know that :L