Answer:
Chemical properties can be recognized only when substances react or do not react chemically with one another, that is, when they undergo a change in composition. A chemical property of one substance usually involves its ability to react or not react with another specific substance.
When you doing a titration, you need to use an indicator to confirm whether the reaction is completed. When the indicator has the color change and will not change back in one minute, the reaction is finished and you don't need to add more.
