- #1
EdTheHead
- 25
- 0
First off how exactly do weak acid strong base reactions work. Let's say I have 1 mole of a weak acid HA in a litre of water and let's say for every 4 undissociated molecules 1 molecules dissociate. So I have about 0.2 moles of H+ ions in this solution then I add some KOH let's say 0.5 moles. I know that there will now be 0.5 moles OH- ions that will snatch all the H+ ions. Once the initial 0.2 moles of H+ ions are converted into water and I'm left with no H+ ions and 0.3 moles of OH- ions what happens? Will the weak acid rapidly dissociate in an attempt to regain its usual equilibrium? In other words will the remaining 0.8 moles of HA rapidly become 6.4 moles of HA and 0.16 H+?
With all that in mind would the HA in this case be buffering the solution by neutralizing any base added but maintaining a specific pH based on its Ka? Would I be right to think that even in this solution the pH will be gradually rising as I'm adding the strong base because although the Ka of the weak acid remains constant the concentration is decreasing therefore there will be less overall H+ ions getting fed into the solution?
With all that in mind would the HA in this case be buffering the solution by neutralizing any base added but maintaining a specific pH based on its Ka? Would I be right to think that even in this solution the pH will be gradually rising as I'm adding the strong base because although the Ka of the weak acid remains constant the concentration is decreasing therefore there will be less overall H+ ions getting fed into the solution?