Question

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

Answer 1

1. Onion and vanilla extract are olfactory indicators.
2. The onion possesses a distinctive odour. When a basic solution, such as sodium hydroxide, is applied to a fabric strip infused with onions (or onion extract), the odour of onions becomes undetectable. Conversely, an acidic solution such as hydrochloric acid does not eliminate the odour of onions. This can serve as a test for acids and bases.
3. Vanilla extract possesses a distinctive and agreeable aroma. When a basic solution, such as sodium hydroxide, is added to vanilla extract, its distinctive aroma becomes undetectable. Conversely, an acidic solution such as hydrochloric acid does not eliminate the aroma of vanilla extract. This can serve as an indicator for acids and bases.