1. Silver(I) ions and iron(II) ions can react according to the following equation:

Ag⁺ (aq) + Fe²⁺ (aq) $\rightleftharpoons$  Ag (s) + Fe³⁺ (aq)

This is an example of a redox equilibrium. The reaction is relatively fast and can reach the equilibrium point within a day.

By titrating the mixture with potassium or sodium thiocyanate solution, the moles of silver ions present at equilibrium can be found. As the thiocyanate solution is added, a white precipitate of silver thiocyanate is formed.

The equation for the reaction that occurs during the titration is:

Ag⁺ (aq) + SCN^– (aq) → AgSCN (s)

When all of the silver ions have been used up, the thiocyanate ions then react with iron(III) ions in the mixture to form a red precipitate of iron(III) thiocyanate, Fe(SCN)²⁺.

Explain why no indicator is needed for the titration.