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Diethyl ether is prepared by:

  1. (a) Dehydration of ethanol with conc. H₂SO₄ at 413 K
  2. (b) Oxidation of ethanol
  3. (c) Reaction of ethanol with Na
  4. (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.

  1. Protonate the alcohol. Conc. H₂SO₄ protonates the -OH of ethanol to give C₂H₅OH₂⁺. Now water is a good leaving group.
  2. 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

    OptionWhat ethanol or the reagent actually gives
    (a) conc. H₂SO₄, 413 Kdiethyl ether (bimolecular dehydration)
    (b) Oxidationethanal, then ethanoic acid
    (c) Nasodium ethoxide and H₂ gas
    (d) Hydrolysis of C₂H₅Clethanol
  3. 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.

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