Single correct · +4 / −1
Diethyl ether is prepared by:
- (a) Dehydration of ethanol with conc. H₂SO₄ at 413 K
- (b) Oxidation of ethanol
- (c) Reaction of ethanol with Na
- (d) Hydrolysis of ethyl chloride
Answer and solution
Answer (a) Dehydration of ethanol with conc. H₂SO₄ at 413 K
Solution
Chemistry ma’am · 3 steps
Two ethanol molecules lose one water between them, and at 413 K that water loss gives you the ether.
- Protonate the alcohol. Conc. H₂SO₄ protonates the -OH of ethanol to give C₂H₅OH₂⁺. Now water is a good leaving group.
- Second ethanol attacks. A second ethanol molecule attacks the carbon of C₂H₅OH₂⁺ by S_N2 and pushes out water. Losing H⁺ then leaves diethyl ether.
2C₂H₅OH →(conc. H₂SO₄, 413 K) C₂H₅-O-C₂H₅ + H₂O
Option What ethanol or the reagent actually gives (a) conc. H₂SO₄, 413 K diethyl ether (bimolecular dehydration) (b) Oxidation ethanal, then ethanoic acid (c) Na sodium ethoxide and H₂ gas (d) Hydrolysis of C₂H₅Cl ethanol - So. Only (a) gives diethyl ether. At the lower temperature of 413 K, two molecules join and lose one water between them. At 443 K the same acid gives ethene instead.
The idea to keep. With conc. H₂SO₄, temperature decides the product: about 413 K gives the ether (two molecules lose one water), about 443 K gives the alkene (one molecule loses water).
Answer from the NTA final answer key. Solution by PrepWiser.