Question

Define olfactory indicator. Write the use of onion extract to distinguish between sodium hydroxide solutions and dilute hydrochloric acid.

Answer 1

1. Olfactory Indicators:

An olfactory indicator is a chemical that changes its odor with the change in pH of the solution and can be used as an indicator to test the nature of the given solution, whether it is acidic or basic.

2. Onion extract:

The onion extract is the extract made from onion peels. It can be used to differentiate the Sodium hydroxide and dilute Hydrochloric acid solutions.

The onion extract smells good in dilute Hydrochloric acid, but its smell is not detectable in Sodium hydroxide solution.