Which chemical process is responsible for the smell of vinegar in an old bottle of $\mathrm{aspirin}$?

• A. Oxidation of $\mathrm{aspirin}$ to form $\mathrm{benzoic} \mathrm{acid}$
• B. Hydrolysis of $\mathrm{aspirin}$ to produce $\mathrm{acetic} \mathrm{acid}$ and $\mathrm{salicylic} \mathrm{acid}$
• C. Esterification of $\mathrm{acetic} \mathrm{acid}$ with $\mathrm{phenol}$
• D. Reduction of $\mathrm{aspirin}$ to $\mathrm{acetaldehyde}$

Answer: (B)

Verified step by step guidance

1. Recognize that aspirin is chemically known as acetylsalicylic acid, which contains an ester functional group formed between salicylic acid and acetic acid.
2. Understand that over time, especially in the presence of moisture, aspirin undergoes hydrolysis, a reaction where water breaks the ester bond.
3. Write the hydrolysis reaction of aspirin: \(\text{acetylsalicylic acid} + \text{H}_2\text{O} \rightarrow \text{salicylic acid} + \text{acetic acid}\).
4. Note that acetic acid is the main component responsible for the characteristic smell of vinegar, which explains the vinegar odor in old aspirin bottles.
5. Conclude that the chemical process responsible for the smell is the hydrolysis of aspirin producing acetic acid and salicylic acid, rather than oxidation, esterification, or reduction.