Identify the final product P₃ in the following reaction sequence:

Step-by-step solution

The starting material is 3,3-dimethylbut-1-ene, (CH₃)₃C-CH=CH₂ . The reaction with HCl begins with the electrophilic addition of a proton to form a secondary carbocation: (CH₃)₃C-C^+H-CH₃ . This carbocation undergoes a 1,2-methyl shift to form a more stable tertiary carbocation: (CH₃)₂C^+-CH(CH₃)₂ . Nucleophilic attack by the chloride ion on this rearranged carbocation yields P₁ , 2-chloro-2,3-dimethylbutane, (CH₃)₂C(Cl)-CH(CH₃)₂ . Treatment of P₁ with alcoholic KOH leads to E2 dehydrohalogenation. According to Say