1-Cyclobutylethanol, CH3CH(OH)-C4H7 (cyclobutyl attached to the carbinol carbon), is heated with conc. H3PO4. After the carbocation rearrangements that relieve ring strain and give the most stable cation, the major alkene is:

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1-Cyclobutylethanol, $CH X_{3} CH (OH) - C X_{4} H X_{7}$ (cyclobutyl attached to the carbinol carbon), is heated with conc. $H X_{3} PO X_{4}$ . After the carbocation rearrangements that relieve ring strain and give the most stable cation, the major alkene is:

Avinylcyclobutane
Bethylidenecyclobutane
C1-methylcyclopentene
D3-methylcyclopentene

Answer: C

The secondary cation next to the four-membered ring undergoes ring expansion (ring C-C bond shift), giving a cyclopentyl cation bearing a methyl group. A hydride shift gives the tertiary 1-methylcyclopentyl cation, and loss of a proton gives the most stable alkene, 1-methylcyclopentene.

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1-Cyclobutylethanol, CHX3​CH(OH)−CX4​HX7​ (cyclobutyl attached to the carbinol carbon), is heated with conc. HX3​POX4​. After the carbocation rearrangements that relieve ring strain and give the most stable cation, the major alkene is:

Answer: C

More questions on Dehydration of alcohols and dehydrohalogenation

1-Cyclobutylethanol, $CH X_{3} CH (OH) - C X_{4} H X_{7}$ (cyclobutyl attached to the carbinol carbon), is heated with conc. $H X_{3} PO X_{4}$ . After the carbocation rearrangements that relieve ring strain and give the most stable cation, the major alkene is: