back to directory
NEET CHEMISTRYHydrocarbonsHard

Question

2,3-dimethyl-2-butene can be prepared by heating which of the following compounds with a strong acid?

A

(Option 1 Structure Missing)

B

(CH3)3C-CH=CH2

C

(CH3)2C=CH-CH2-CH3

D

(CH3)2CH-CH2-CH=CH2

Step-by-Step Solution

  1. Reaction Type: Heating an alkene or alcohol with a strong acid (like H2SO4H_2SO_4) typically leads to the formation of a more substituted alkene via the formation of a carbocation intermediate and subsequent rearrangement.
  2. Analysis of Option 2 ((CH3)3C-CH=CH2): This compound is 3,3-dimethylbut-1-ene.
  • Protonation: The acid protonates the double bond to form a secondary carbocation: (CH3)3C−CH+−CH3(CH_3)_3C-CH^+-CH_3.
  • Rearrangement: A 1,2-methyl shift occurs to form a more stable tertiary carbocation: (CH3)2C+−CH(CH3)2(CH_3)_2C^+-CH(CH_3)_2.
  • Elimination: Elimination of a proton from the adjacent carbon yields the most substituted, stable alkene (Saytzeff product): 2,3-dimethylbut-2-ene ((CH3)2C=C(CH3)2)((CH_3)_2C=C(CH_3)_2).
  1. Conclusion: The rearrangement of the carbon skeleton in 3,3-dimethylbut-1-ene under acidic conditions leads directly to the formation of 2,3-dimethyl-2-butene.

Exam Context & Concepts Covered

This question aligns with the NEET CHEMISTRY syllabus, specifically targeting concepts from Hydrocarbons. Mastering this topic is crucial for scoring well in the upcoming medical entrance examinations. Solving conceptually related problems will help you understand the nuances of these concepts and improve your problem-solving speed.

CHEMISTRYHydrocarbonsdimethylbutenepreparedheatingfollowingcompounds

More Hydrocarbons Questions

View all

Phenylacetylene undergoes a reaction with dilute $\text{H}_2\text{SO}_4$ in the presence of $\text{HgSO}_4$ to yield:

A.Option 1 (Structure missing)
B.Option 2 (Structure missing)
C.Option 3 (Structure missing)
D.Option 4 (Structure missing)
MediumSolve

The reaction among the following that proceeds through an electrophilic substitution reaction is:

A.(Option 1 Structure Missing)
B.(Option 2 Structure Missing)
C.4
D.(Option 4 Structure Missing)
EasySolve

The order of decreasing reactivity towards an electrophilic reagent for the following compounds is: (i) Benzene (ii) Toluene (iii) Chlorobenzene (iv) Phenol

A.(i) > (ii) > (iii) > (iv)
B.(ii) > (iv) > (i) > (iii)
C.(iv) > (iii) > (ii) > (i)
D.(iv) > (ii) > (i) > (iii)
MediumSolve

X and Y in the above-mentioned reaction are respectively:

A.X = 2–Butyne; Y = 3–Hexyne
B.X = 2-Butyne; Y = 2-Hexyne
C.X = 1-Butyne; Y = 2-Hexyne
D.X = 1-Butyne; Y = 3–Hexyne
MediumSolve

Match the bond line structures of hydrocarbons given in List-I with the corresponding boiling points given in List-II. List-II (Boiling point in K): (i) 300.9 (ii) 282.5 (iii) 309.1 (iv) 341.9 Choose the correct answer from the options given below:

A.(a)-(i), (b)-(iv), (c)-(iii), (d)-(ii)
B.(a)-(iii), (b)-(i), (c)-(iv), (d)-(ii)
C.(a)-(iii), (b)-(iv), (c)-(i), (d)-(ii)
D.(a)-(iv), (b)-(i), (c)-(ii), (d)-(iii)
MediumSolve

The dihedral angle of the least stable conformer of ethane is:

A.$60^{\circ}$
B.$0^{\circ}$
C.$120^{\circ}$
D.$180^{\circ}$
EasySolve

Phenanthrene is an aromatic compound and follows Hückel's $(4n+2)\pi$ electron rule. The value of $n$ is:

A.0
B.1
C.2
D.3
MediumSolve

The correct statement regarding the comparison of staggered and eclipsed conformations of ethane is:

A.The eclipsed conformation of ethane is more stable than staggered conformation because eclipsed conformation has no torsional strain.
B.The eclipsed conformation of ethane is more stable than staggered conformation even though the eclipsed conformation has a torsional strain.
C.The staggered conformation of ethane is more stable than eclipsed conformation because staggered conformation has no torsional strain.
D.The staggered conformation of ethane is less stable than eclipsed conformation because staggered conformation has a torsional strain.
EasySolve

Why 32,000+ students choose TopperSquare

Everything you need to crack NEET

15,000+ Chapter MCQs

Physics, Chemistry, Biology — chapter-wise, topic-wise practice

AI Performance Analytics

Know your weak topics. Get a personalised study plan.

Full NEET Mock Tests

180 questions, timed, with detailed score analysis

PYQ Sets 2010–2024

15 years of past papers with solved explanations

Start Practising Free

No credit card · 30-second signup · Free forever plan included

This neet chemistry practice question is part of the TopperSquare free question bank. TopperSquare offers 15,000+ chapter-wise NEET MCQs across Physics, Chemistry, and Biology with detailed step-by-step explanations, full mock tests, NEET PYQs (2010–2024), and an AI-powered performance analytics dashboard. browse all neet practice questions → · practice chemistry sets →

Explore more subjects:Physics MCQs•Chemistry MCQs•Biology MCQs•Botany MCQs•Zoology MCQs•NEET Mock Tests•NEET PYQs