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.