The pH of the solution at equivalence point is dependent on the strength of the acid and strength of the base used in the titration.
For strong acid-strong base titration, pH = 7 at equivalence point For weak acid-strong base titration, pH > 7 at equivalence point For strong acid-weak base titration, pH < 7 at equivalence point
The indicator changes color when the pH changes at the endpoint of the titration. So, you need to determine what is present at the point and find the pH at the point. Then, you can reference a table of indicators to choose one whose color will change over the pH that includes your equivalency point.
En la reacción entre el litio y el oxígeno, el litio cede su electrón de valencia al átomo de oxígeno. Como puede verse en la animación de la derecha, dos átomos de litio reaccionan con un átomo de oxígeno. Cada átomo de litio le da un electrón al átomo de oxígeno.
