Question

Why does turmeric turns red with surfwith soap?

Answer 1

Because turmeric acts as acid base natural indicator which changes its colour in the presence of an acid.

Answer 2

The water turns turmeric back to yellow. ⇒ A stain of curry on white cloth becomes reddish brown when soap is rubbed because curry contain turmeric which is a natural indicator whereas soap is basic in nature. when turmeric react with soap it turn into reddish brown.