The weak acid strong base titration is the process of direct transfer of protons from the weak acid to the hydroxide ion. To better understand, the example of the reaction of a weak acid or acetic acid with a strong base, NaOH is written below in which the acid and the base react in a one to one ratio.
C2H4O2 (aq)+ OH- (aq) gives (=) C2H3O2- (aq) + H2O (l)
In this reaction, a buret has been used to administer one of the solutions to the other and the solution that is administered from the buret is known as the titrant and the solution in which the titrant is added is called the analyte. So in the weak acid strong base titration, the titrant is a strong base and the analyte is the weak acid. And so in order to completely understand this type of titration, the titration curve was introduced.
So as you scroll down, you will find out all the details about the characteristics of the titration curve of the weak acid and strong base which will give you complete insight on the titration process. So scroll down to find out all the information about it.
The Titration Curve of weak acid strong base titration
The titration curve is mainly a graph which shows the volume of the titrant, or when the volume of a strong base is plotted against the pH. There are many characteristics which are seen in all the titration curves of weak acid strong base. So these characteristics shows by the curve are listed below:
- The most initial pH, just before the addition of any strong base in it, is quite higher or we can say it is less acidic than the titration of strong acid.
- There is a sharp increase seen in the pH in the start of the titration and this happens because the anion of the weak acid becomes a common ion which reduces all the ionisation of the acid.
- After this sharp increase happens at the start of the titration, the curve starts to change gradually and this happens because the solution starts to act as a buffer. And so this will continue until the base overcomes the capacity of the buffer.
- Now, the half-neutralisation happens in the middle of this gradual curve. This is the point when the concentration of the weak acid becomes equal to the concentration of its conjugate base. And thus the pH=PKa. This is the point which is called the half-neutralisation because at this point, half of the acid has been neutralised.
- Now, at the point of equivalence, the pH becomes greater than 7 as all the acid (HA) was converted to its conjugate base (A-) by the addition of the NaOH. thus, the equilibrium moves blackboard towards HA and procure hydroxide here which is as-
A- + H2O = AH + OH-
- And finally the steep portion of the curve which is prior to the point of equivalence is short and it mainly occurs until a pH of around 10.
And as you have read now about the characteristics of the titration curve of the weak acid strong base titration, you can also go and search for an image of this titration curve which will help you to understand a lot better.
Conclusion
The weak acid strong base titration is basically the process of direct transfer of protons from the weak acid to the hydroxide ion. The titration curve was introduced later to understand the complete process of titration by looking at its characteristics and about which you must have read above.
