AI-generated practice question — model-generated for extra practice, not a previous-year CBSE board question.
Two natural acid-base indicators are litmus (extracted from lichen) and turmeric.
The introduction of Chapter 2 explicitly mentions litmus and turmeric as natural indicators. Litmus is extracted from lichen (a plant of division Thallophyta). Coloured petals of flowers like Hydrangea, Petunia, and Geranium, as well as red cabbage leaves, are also acceptable answers — any two from this list will earn the mark.