Question

Turmeric strip do not show any color change in acid. So how we would know that the given substance is acid or neutral

Answer 1

Turmeric doesn't give any colour with acids.
But we can use other natural indicators like litmus paper and China rose.
Colour of litmus paper in acid: Blue litmus paper turns into red when dipped in acidic solution.

China rose solution gives dark pink (magenta) colour with acid.

With litmus and China rose neutral doesn't show any colour and hence we can easily identify them.