Question

What is the product Y in the following chemical reaction? 

• A. \(\text{C}_{2}\text{H}_{5}\text{OCH}_{3}\)
• B. \(\text{C}_{2}\text{H}_{5}\text{OC}_{2}\text{H}_{5}\)
• C. \(\text{CH}_{3}\text{OCH}_{3}\)
• D. \(\text{H}_{2}\text{C}=\text{CH}_{2}\)

Hint:

Remember: Ethanol + Conc. \(\text{H}_2\text{SO}_4\) at \(443\,K\) gives ethene, while at lower temperature (\(\sim413\,K\)) it forms diethyl ether.

Answer 1

The Correct Option is D

Concept: Alcohols undergo dehydration in the presence of concentrated sulphuric acid. The product formed depends on temperature. At \(413\,K\), ethers are generally formed. At \(443\,K\), alkenes are formed by elimination of water.

Step 1: Identify the reactant.
The given alcohol is ethanol, \[ \text{CH}_{3}\text{CH}_{2}\text{OH} \] which is a primary alcohol.

Step 2: Apply dehydration reaction.
When ethanol is heated with concentrated sulphuric acid at \(443\,K\), \[ \text{CH}_{3}\text{CH}_{2}\text{OH} \rightarrow \text{CH}_{2}=\text{CH}_{2} + \text{H}_{2}\text{O} \] Water is eliminated and ethene is formed.

Step 3: Identify the product.
The product obtained is \[ \text{H}_{2}\text{C}=\text{CH}_{2} \] which is ethene.