Certain food items like lemons, tamarind, and vinegar are sour to taste, while some substances like soap are slippery to touch and bitter in taste. It has been found that these items contain acids and bases. However, it is not safe to determine the nature of items by tasting or touching them. This is where indicators help us. Indicators are substances that change color in the presence of an acid or base, making it easier to identify their nature.

In this activity, you’ll explore some commonly used laboratory indicators and see how they help us identify the nature of different solutions.