What are the common indicators used?
Turmeric is another common household indicator. A stain of turmeric based food spill on a white cloth becomes reddish-brown when soap is scrubbed on it. Soap is basic in nature and changes the colour of the turmeric stain. It turns yellow again when the cloth is washed with plenty of water. Other indicators— • Red cabbage extract gives red colour in acidic solutions & yellow colour in basic solutions. • Onion has a characteristic smell. In basic solutions like NaOH, there is no smell. Acids however, do not destroy the smell of onions. • Vanilla extract has a pleasant smell in acidic solutions, in basic solutions there is no smell.
