Examples:

Titration of azobenzene within acidic solution with V (II)

If one of the couples is irreversible the shape of the curve will be different.

Eg:  titration of iodine through thiosulphate. In that case, iodide-iodine couple is reversible and titrant thiosulphate-tetrathionate couple is irreversible. The titration curve will be as in Figure.

I²    +   2e^- ↔  2I^-

2S₂O₃^2- ↔       S₄O₆^2- + 2e^-

While iodine in a solution holding iodide is titrated along with thiosulphate, the anode will oxidize iodide ion and cathode will decrease iodine since iodide- iodine couple is reversible. As more and more iodine is removed from the solution through adding more and more thiosulphate the current will decrease, since there is less iodine available for reduction at the cathode. At last, at the end point, the iodine is fully removed from the solution and the current will be closely zero. After the end point, as more thiosulphate is added, the current remains the similar since the titrant couple is irreversible and the applied potential value is small.