Concept:The sulfuric acid-catalyzed dehydration of primary alcohols (like ethanol) is temperature-dependent, shifting between intermolecular and intramolecular pathways.
Formula:$$ 2\text{C}_2\text{H}_5\text{OH} \xrightarrow[140^{\circ}\text{C}]{\text{Conc. H}_2\text{SO}_4} \text{C}_2\text{H}_5\text{-O-}\text{C}_2\text{H}_5 + \text{H}_2\text{O} $$
Solution:- At the lower temperature of 140°C, a bimolecular (intermolecular) condensation occurs.
- One molecule of ethanol loses an -OH group, and another loses an -H atom, linking the two chains via an oxygen bridge.
- This yields an ether, specifically diethyl ether.
Why other options are incorrect:At a higher temperature (170°C), intramolecular dehydration occurs to yield ethene. Acetaldehyde requires oxidation. Ethyl acetate requires reaction with acetic acid. Ethyl chloride requires HCl.
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