In a titration, what term denotes the colour-change point observed by the indicator?

• A. Titrant
• B. Half cell
• C. Electrolyte
• D. Endpoint

Answer: (D)

The endpoint is the color-change point observed by the indicator. In a titration, the indicator is chosen so its color change occurs right around the point where the reaction has been driven to completion, signalling that enough titrant has been added. That observed color shift is what we call the endpoint. The actual moment when the amounts of titrant and analyte have reacted perfectly (the equivalence point) is a chemical concept, while the endpoint is the observable event defined by the indicator. The other terms don’t describe a color change: the titrant is the solution being added, a half cell is part of an electrochemical cell, and an electrolyte is a substance that provides ions in solution.