Question

Why does the stain of curry on a white cloth becomes reddish brown when soap is rubbed on it and turns yellow when cloth is washed in water?

Answer 1

the stain of curry on a white cloth becomes reddish brown when soap is rubbed on it and turns yellow when cloth is washed in water because -
Turmeric has a pigment known as xanthophylls, which lends the yellow colour to it. It also has a pigment called as carotene, which is reddish orange in colour. When turmeric comes in contact with detergent or soap it reacts with the fatty acids present in the detergent/soap and hence the carotene pigment gets more active than the xanthophylls and turmeric turns red.
When turmeric is combined with any base liquid like soap it turns red in colour while when turmeric comes in contact with any substance like that of vinegar, that is acidic in nature, it turns yellow.

Answer 2

Answer:

Becoz curry contains turmeric . Turmeric is an indicator which gives red colour with a base since soap is a base so we get red colour....

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