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Titration curve- weak acids and bases

In the titration curve for a weak acid and weak base, there is no sharp jump at the equivalence point unlike for the other curves. My book says this is due to the fact that there are several equilibria involved. What are these several equilibria?

Reply 1

Borek

What equilibria are present in a solution containing weak acid? Weak base? Just water?

Acetic acid and ammonia (both 0.1M):

acetic_acid_titrated_with_ammonia.png1.6KB

Reply 2

Aaradhana

Original post by Borek

What equilibria are present in a solution containing weak acid? Weak base? Just water?

Acetic acid and ammonia (both 0.1M):

Okay, I know that I'm going to sound completely dumb here but this is a chapter I have tried very hard, to understand, but I just don't get it... So I get the point there is no sharp jump but what exactly do you mean? Equilibrium can exist at any point of the graph right? I mean at every point the reaction has a different equilibrium with different concentrations of reactants and products so I really don't get this...

Reply 3

Borek

At each point of the curve you have at least one buffer (acetic before the end point, ammonia after) that resists pH changes. That makes them slow.

Reply 4

Aaradhana

Original post by Borek

At each point of the curve you have at least one buffer (acetic before the end point, ammonia after) that resists pH changes. That makes them slow.

Oh so what they meant is that the equilibriums can be generalised into three: one before the end point, one on the end point and one after the end point. And there are buffers on both sides of the end point so there is no sharp jump. Did I get it right?