Final answer:
Garlic breath is caused by prop-2-ene-1-thiol and other sulfur-containing compounds such as methanthiol found in garlic. These compounds are released during consumption and lead to the distinctively strong and often lingering odor of garlic breath.
Step-by-step explanation:
The chemical responsible for garlic breath is primarily due to the presence of sulfur-containing compounds known as thiols. Specifically, prop-2-ene-1-thiol (CH2=CH-CH2-SH) contributes significantly to the strong odor characteristic of garlic. Other sulfur compounds, such as methanthiol, are also present in garlic and contribute to its potent aroma and the resulting bad breath after consumption.
Sulfur compounds are known for their strong and often unpleasant odors. For instance, hydrogen sulfide (H₂S) is known for its rotten egg smell, while thiols and thioethers can have similarly disagreeable scents. These compounds are released in the mouth and can be exhaled, leading to garlic breath that is difficult to mask.