Question

When ethanol is heated with conc. H₂SO₄, a gas is produced. The compound formed, when this gas is treated with cold dilute aqueous solution of Baeyer’s reagent, is

• A. Formaldehyde
• B. Formic acid
• C. Glycol
• D. Ethanoic acid

Answer 1

The Correct Option is C

To solve this problem, let's consider the chemical reactions that occur when ethanol is heated with concentrated sulfuric acid and then treated with Baeyer's reagent.

1. Dehydration of Ethanol: When ethanol (\(\text{C}_2\text{H}_5\text{OH}\)) is heated with concentrated sulfuric acid (\(\text{H}_2\text{SO}_4\)), it undergoes a dehydration reaction to form ethene (\(\text{C}_2\text{H}_4\)), a gaseous compound. The reaction is as follows: \(\text{C}_2\text{H}_5\text{OH} \xrightarrow[]{\text{conc.}\ \text{H}_2\text{SO}_4} \text{C}_2\text{H}_4 + \text{H}_2\text{O}\)
2. Treatment with Baeyer's Reagent: Baeyer's reagent is a cold dilute aqueous solution of potassium permanganate (\(\text{KMnO}_4\)), which is a test for unsaturation. When ethene (\(\text{C}_2\text{H}_4\)) is treated with Baeyer's reagent, it gets oxidized to form ethylene glycol (\(\text{C}_2\text{H}_4(\text{OH})_2\)), a type of glycol. The reaction is: \(\text{C}_2\text{H}_4 + \text{O} + \text{H}_2\text{O} \rightarrow \text{C}_2\text{H}_4(\text{OH})_2\)
3. Conclusion: The correct answer is glycol since ethylene glycol (\(\text{C}_2\text{H}_4(\text{OH})_2\)) is formed when ethene is treated with Baeyer's reagent. The options formaldehyde, formic acid, and ethanoic acid do not result from this sequence of reactions.

Hence, the correct answer is Glycol.