posted by Fiona on .
Why is a solution of KNO3 neutral and not acidic?
K^+ doesn't hydrolyze (H2O has a stronger attraction for the OH- than K^+) and NO3^- doesn't hydrolyze (H2O is a stronger base than NO3^- meaning that H2O will not donate a proton to NO3^-).
Looking at it another way, suppose it did, what would we get?
KNO3 + HOH ==> KOH + HNO3.
BUT KOH is a strong base and HNO3 is a strong acid and there is no driving force for the reaction to occur. Remember, three reasons for a reaction to go to completion:
1. gas is formed (neither is a gas).
2. ppt is formed (neither is a ppt).
3. slightly ionized substance is formed (neither is a weak electrolyte).
So, no reaction when KNO3 is placed in water, except for the crystal structure breaking and forming K^+(aq) and NO3^-(aq).