Question

What is an olfactory indicator? Name two olfactory indicators. What is the effect of adding sodium hydroxide solution to these olfactory indicators?

Answer 1

Hint: We characterize indicators are weak acids that exist as characteristic colors and demonstrate the centralization of particles during an answer through shading change. The estimation is resolved from the negative logarithm of this focus and is locked in to point to the acidic, essential, or nonpartisan nature of the substance you're trying.

Complete step by step answer:
Let us solve these questions in parts.
We have to remember that the olfactory indicators are indicators which identify acids and bases on the basis of smell or odour. The word ‘olfactory’ means relating to the sense of smell. When these indicators are added to acids or bases, the change in smell is used to identify whether the solution contains acid or a base. When an olfactory indicator is added to a solution containing acids, there is no change in the smell of the solution. But when the same is added to a solution containing bases, the smell changes, i.e, no smell can be detected.
Two examples of olfactory indicators are Onion and vanilla extracts. When either of the two are mixed with a solution containing an acid, the smell of the indicator does not change. Whereas, when mixed with a solution containing a base, the smell of the indicator fades away and cannot be detected. Thus, these two indicators can be used to identify the solution as acid or base.
The effect of adding sodium hydroxide solution to these olfactory indicators can be predicted by understanding whether the given solution is an acid or a base. As indicated by the molecular formula of sodium hydroxide-NaOH, It is obvious that it is a basic solution due the presence of –OH groups. Hence, an olfactory indicator, say for example Onion extracts are added to a basic NaOH solution, the strong pungent smell of an onion fades away and cannot be detected.

Note: In order to understand the nature of indicators when added to an acid or base, it must be clear that indicators work in the rule that bases fade the smell of the indicator and acids have no change in the smell or odour of the indicator. This knowledge of indicators can also help detect where the solution added is acidic or basic.