Question

why does a turmeric stain turn red when washed with a soap

Answer 1

Turmeric is a natural indicator of acidic or basic nature, like litmus paper. It turns red when it comes in contact with bases. Since soap is basic, turmeric turns red when it is washed with soap.

Answer 2

as we know turmeric is acidic in nature so due to chemical reaction with a basic substance it turns red in color . hence acid is powerful than base