Question

1. How are natural indicators prepared? Give examples of a flower, root, stem and leaf that
can be used as an indicator. What are the colour changes observed with red cabbage
juice in acidic, neutral and basic medium?

Answer 1

Answer: Turmeric - It is the most common natural indicator which can be easily available. The solution of turmeric is applied on papers and from it paper strips are made. - Take some turmeric powder and mix it in water to form a thin paste. - Apply this paste on the filter paper and let it dry for some time.: Red cabbage contains a water-soluble pigment called anthocyanin that changes color when it is mixed with an acid or a base. The pigment turns red in acidic environments with a pH less than 7 and the pigment turns bluish-green in alkaline (basic) environments with a pH greater than 7