Acid-base Titration Curves

A reaction between an acid and an alkali is known as a neutralisation.
The concentration of an acid can be determined by titrating it against a standard alkali solution using a suitable indicator, and the concentration of an alkali can be determined by titrating against a standard acid solution.
If solution A is titrated against solution B, it means that solution A is in the conical flask and solution B is in the burette.
The behaviour of acid-alkali mixtures during titrations depends on whether the acids and bases are strong or weak.
The equivalence-point of a titration is where stoichiometrically equivalent amounts of acid and base have reacted together.
Acid-base indicators are used in the titration to determine the equivalence point.
The end-point of a titration is where the acid-base indicator changes colour.
A suitable indicator is one that has a pH range where it changes colour coincides with the end-point.

The titration curves start at 14 and 1 which indicate the presence of a strong base and alkali respectively.
The sharp decrease/increase in pH indicates the equivalence point of the titration.
The pH of resulting salt solution at the equivalence point is 7 as the salt formed is not acidic or basic and hence does not undergo hydrolysis.
No buffer regions formed as no weak acid or base is used.
When excess acid or base is added, the resulting solutions have a pH of 1 and 14 which also indicates the addition of strong acid and strong base respectively.

The titration curves start at 14 and 3 which indicates the presence of a strong base and weak acid respectively.
The sharp decrease/increase the pH indicates the equivalence point of the titration.
At the equivalence point, the basic salt formed undergoes hydrolysis.
A-(aq) + H2O(l) → HA(aq) + OH-(aq)
OH- ions produces results in pH > 7 at the equivalence point
If you recall from the earlier chapter, a weak acid and its conjugate base salt form a buffer solution, thus a buffer region is formed as the base is added to excess acid. pH changes more slowly.
When the excess acid/base is added, the resulting solutions have a pH of 3 and 14 which indicate the addition of weak acid and strong base respectively.

The titration curves start at 11 and 1 which indicates the presence of a weak base and strong acid respectively.
The sharp decrease/increase in pH indicates the equivalence point of the titration.
At the equivalence point, the acidic salt formed undergoes hydrolysis.
HB+ (aq) ⇌ B(aq) + H+(aq)
H+ ions produced result in pH < 7 at equivalence-point.
When we start adding acid to a weak base, its conjugate acid salt is formed resulting in an alkaline buffer region. pH changes more slowly.
When excess acid or base is added, the resulting solutions have a pH of 11 and 1 again indicating the presence of a weak base and strong base.

The titration curves start at 11 and 3 which indicates the presence of a weak base and weak acid respectively/.
The pH changes gradually and there is no sharp decrease in pH.
At the equivalence point, the salt formed undergoes hydrolysis.
HB+(aq) ⇌ B(aq) + H+(aq)
A-(aq) + H2O(l) ⇌ OH-(aq) + HA(aq)
Amount of H+ and OH- ions formed in hydrolysis is approximately equal so the pH at equivalence point is 7.
No buffer regions are formed.
When excess acid or base is added, the resulting solutions have a pH of 3 and 11 which indicate the addition of weak acid and weak base respectively.

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