Methanol on heating with salicylic acid and a few drops of conc. $H_{2}SO_{4}$ gives the smell of :

Question

Accepted Answer

Methanol on heating with salicylic acid and a few drops of concentrated sulfuric acid ($H_{2}SO_{4}$) undergoes an esterification reaction to form methyl salicylate. Methyl salicylate is an organic ester that is commonly known as "Oil of Wintergreen" due to its characteristic minty aroma. This is why Option 2, "Oil of Wintergreen," is the correct answer.

1. **Explanation for Option 2:**
   - **Chemical Reaction:** The reaction between methanol and salicylic acid in the presence of concentrated sulfuric acid leads to the formation of methyl salicylate. The reaction is as follows:
     $$
     \text{Salicylic Acid} + \text{Methanol} \xrightarrow{\text{conc. } H_{2}SO_{4}} \text{Methyl Salicylate} + \text{Water}
     $$
   - **Aroma:** Methyl salicylate has a distinct wintergreen scent, which is why it is often used in flavorings and fragrances. This characteristic smell is what is referred to as "Oil of Wintergreen."

2. **Explanation for why other options are incorrect:**
   - **Option 1: Bitter almonds** - The smell of bitter almonds is typically associated with benzaldehyde or hydrogen cyanide, not methyl salicylate. Therefore, this option is incorrect.
   - **Option 3: Rotten eggs** - The smell of rotten eggs is due to hydrogen sulfide (H₂S), a gas with a very different chemical composition and origin than methyl salicylate. Thus, this option is incorrect.
   - **Option 4: Mustard oil** - Mustard oil has a pungent smell due to allyl isothiocyanate, which is unrelated to the esterification reaction between methanol and salicylic acid. Hence, this option is incorrect.

In conclusion, the reaction between methanol and salicylic acid in the presence of concentrated sulfuric acid produces methyl salicylate, which has the characteristic smell of "Oil of Wintergreen," making Option 2 the correct choice.