Final answer:
A redox titration without using an indicator involves measuring the electrical potential difference using a voltmeter. The potential difference decreases as the reactants are consumed until it reaches a steady value, indicating the end point.
Step-by-step explanation:
A redox titration without using an indicator involves measuring the electrical potential difference (voltage) using a voltmeter. The principle behind this is that in a redox reaction, the transfer of electrons generates an electrical potential. By measuring this potential difference, we can determine the equivalence point of the titration. When the potential difference stops changing, it indicates that the reactants have reacted completely.
For example, in an oxidation-reduction reaction between zinc and copper ions, we can connect a zinc electrode and a copper electrode to a voltmeter and measure the potential difference. Initially, the potential difference will be high, indicating high concentrations of reactants. As the reaction progresses and the reactants are consumed, the potential difference decreases until it reaches a steady value, indicating the end point of the titration.