Give two examples of flowers which act as natural indicator.

Question

what is the colour change observed in basic medium?

thank u

Answer 1

Hydrangea is the best known.  Its flowers are pink when grown in basic soil and blue when grown in acidic soil.

Many, many flowers and fruits that are red/purple/blue use compounds called anthocyanins for coloration.  These compounds are pH indicators, being red in acid and blue/green in base.  One example is the pansy, according to a caption on the wikipedia article.