Question

how do they use vanilla as an olfactory indicators​

Answer 1

Answer:

All onion,clove oil and vanilla extract are examples. An olfactory indicator works on the principle that when an acid or base is added to it,then different odour can be detected in bases whereas odour remains same in acids.Certain substances changes odour in acidic or basic medium.

Answer 2

Answer:

vanilla is an olfactory indicator.They change their smell when exposed to an acid or base. When they are exposed to an acid , they retain their smell whereas when exposed to a base they lose their smell. this is how they use vanilla as an olfactory indicator