Lemon does not actually absorb odors. It has antibacterial abilities that can kill the bacteria that make the odors leaving only its citrus scent.
A lemon absorbs every color but yellow, which it reflects.
No
There are many things that can be smelled but not seen. For example, an odorant is added to otherwise odorless natural gas so that it can be detected. This odorant cannot be detected by sight.
odorant
bind to receptors in olfactory cilia.
Mercapton is a strong odorant added to natural gas supplies prior to distribution.
Mercapta is added to LPG to make sure wheather it is leaking or not.
G-Protein
donator, odorant, tandoor, tornado
rosemary (a small bush with mall, odorant leaves) is 'le romarin' in French.
Ethanethiol is commonly used as an odorant in LPG to detect leaks.
The reaction between baking soda and citric acid is a neutralization and therefore endothermic. It absorbs energy from its environment rather than exerting it.