Why does a yellow curry stain on a white shirt turn red when it is washed with soap ?

A yellow stain of turmeric containing curry on a white shirt turns red when soap solution is scrubbed on it. This shows that soap solution is :

Why hard water does not give lather with soap?

Vinay observed that the stain of curry on a white shirt becomes reddish-brown when soap is scrubbed on it, but it turns yellow again when the shirt is washed with plenty of water. What might be the reason for his observation? i. Soap is acidic in nature ii. Soap is basic in nature iii. Turmeric is a natural indicator which gives reddish tinge in bases iv. Turmeric is a natural indicator which gives reddish tinge in acids

Why does hard water not from lather with soap ?

Meena rubbed the yellow coloured turmeric stain on his son's shirt with soap. She observed the colour of the stain became: