Start learning →

JEECUP (UP Polytechnic) Dehydration — practice questions

Explore 2 free Dehydration questions in JEECUP (UP Polytechnic) Chemistry. Open each question or exercise to read its content, reference answers and available explanation.

Practise Dehydration with Quill →

Dehydration questions and exercises with answers

Showing questions 1–2 of 2.

**Dehydration** of alcohols to alkenes with concentrated H₂SO₄ follows the order:Read the answer and worked solution →Order of **dehydration rate** of alcohols R-CH₂-OH, R₂-CHOH, R₃-COH (R = CH₃) with conc. H₂SO₄ is:Read the answer and worked solution →

Worked practice questions

**Dehydration** of alcohols to alkenes with concentrated H₂SO₄ follows the order:

  1. 1° > 2° > 3°
  2. 3° > 2° > 1° (more stable carbocation favours E1)
  3. All equal
  4. Aromatic > aliphatic
Show answer and solution

Correct answer: B. 3° > 2° > 1° (more stable carbocation favours E1)

**E1 dehydration:** more stable carbocation forms faster. 3° (most stable cation, lowest activation E) > 2° > 1°. Tertiary alcohols dehydrate even at lower temperatures (~20% H₂SO₄, ~85 °C) primary need conc. H₂SO₄, ~170 °C.

Open this question →

Order of **dehydration rate** of alcohols R-CH₂-OH, R₂-CHOH, R₃-COH (R = CH₃) with conc. H₂SO₄ is:

  1. 1° > 2° > 3°
  2. 3° > 2° > 1° (E1 mechanism, more stable cation = faster)
  3. 2° > 3° > 1°
  4. All equal
Show answer and solution

Correct answer: B. 3° > 2° > 1° (E1 mechanism, more stable cation = faster)

E1 dehydration rate ∝ carbocation stability. 3° alcohol → 3° carbocation (most stable) → fastest. **Conditions:** 3° at 20%H₂SO₄, 85 °C 2° at 60%, 100 °C; 1° at 95%, 170 °C.

Open this question →

How to practise

  1. Choose a Dehydration question and try to work out your answer.
  2. Open the question to check the correct answer and read its worked solution.
  3. Continue in the app for bite-sized lessons, explanations and review with Quill. You can start without creating an account.

More Chemistry topics

Ideal and Non-Ideal SolutionsIdeal SolutionsNon-Ideal SolutionsReactions in Aqueous SolutionElectrochemistryElectrochemical SeriesCoordination CompoundsSolutions