Answer to Question #156443 in General Chemistry for Sayra

Question

In a laboratory analysis, you are required to standardize the prepared sodium thiosulfate

pentahydrate (Na 2 S 2 O 3 .5H 2 O) solution by performing titrimetric method, with which the

indicator is starch. When can you say that the reaction is complete? Just give the general

condition.

Answer 1

Watch the solution closely for the color change. Once the solution begins to change color and the new color persists for at least 30 seconds, you have reached the end point of your titration.