Final answer:
The alkene formed from the dehydration of tert-butyl alcohol ((CH3)3COH) in an acidic medium is isobutylene (2-methylpropene), with the formula (CH3)2C=CH2.
Step-by-step explanation:
The question refers to the formation of an alkene from tert-butyl alcohol (also known as (CH₃)₃COH) through a reaction with water in an acidic solution. This process is called the dehydration of alcohols, which typically converts alcohols to alkenes. Tert-butyl alcohol is a tertiary alcohol, meaning that the OH group is attached to a carbon atom connected to three other carbon atoms. When reacting in an acidic medium, this alcohol undergoes dehydration to form an alkene.
However, for tert-butyl alcohol, the dehydration leads to the formation of isobutylene (2-methylpropene). The formula for isobutylene is (CH₃)₂C=CH₂. This reaction proceeds through a carbocation intermediate, and due to the tertiary nature of the starting alcohol, it is more likely to undergo dehydration than primary or secondary alcohols.