Which chemical compound is known for being the longest lasting?

The correct choice is phenol, which is recognized for its stability and lasting power in various applications. Phenol has a strong molecular structure that allows it to resist degradation over time, especially compared to other chemical compounds like formaldehyde, alcohol, and hydrogen peroxide.

Formaldehyde does provide lasting preservation effects, particularly in embalming, but it can break down more quickly under certain conditions, such as exposure to light and certain temperatures. Alcohol, while effective as a disinfectant and preservative, evaporates quickly and does not provide the same long-term stability as phenol. Hydrogen peroxide, while useful for its oxidizing properties and as a disinfectant, has a limited shelf life and decomposes into water and oxygen, reducing its lasting effectiveness.

In summary, the robust nature of phenol's molecular structure contributes to its reputation as the longest-lasting compound among those listed, making it particularly valuable in applications requiring durability and extended efficacy.