Question

which of these Vanilla onion and Clove can we use of olfactory indicator on the basis of you observation?among this which one is better ?

Answer 1

both of them can be used. Onion:- Paste or juice of onion loses its smell when added with base.It does not change its smell with acid.
2.Vanilla:- The smell of vanilla vanishes with base,but it’s smell does not vanishes with an acid.
3.Clove oil- In bases its characteristis smell cannot be detected.

Answer 2

These all substance are better...

Onion has a characteristic pleasant smell. When a basic solution like sodium hydroxide solution is added to a cloth strip treated with onions , then the onion smell cannot be detected.An acidic solution like hydrochloric acid, however, does not destroy the smell of vanilla extract ...This can be used as a test for acid and bases.....