Question

How do you know when the endpoint is reached in a titration? When does this occur?

Answer 1

Before a titration, indicator is added to the analyte (which is in the flask, and usually the chemical of unknown concentration).  The titrant is then placed in a burette and slowly titrated into the analyte.  When the indicator changes color is when the endpoint of the titration has been reached.  This occurs (approximately) at the equivalence point.