Answer to Question #147810 in General Chemistry for liam donohue

Question

For the Acid-base titration experiment if you left the final solution to stand for a long period of time, the colour will fade from blue to yellow. What does this indicate and what gas in the atmosphere is causing this chemical transformation? What is the reaction?

Answer 1

The endpoint has been reached when a faint pink color persists for at least 30 seconds. It is easy to overshoot the endpoint. If this happens, you will have a dark purple-pink solution, and you will have to repeat the titration, so be careful.