What is the major product [Z] formed when compound [C] undergoes the following reactions:

Step-by-step solution

Compound [C] is 2-bromo-3-methylbutane. Dehydrohalogenation of [C] with alcoholic KOH and heat yields the more substituted alkene (Saytzeff's rule) as the major product. Thus, [X] is 2-methylbut-2-ene, CH₃-CH=C(CH₃)₂ . Electrophilic addition of HCl to [X] follows Markovnikov's rule. Protonation forms the more stable tertiary carbocation, which captures a chloride ion to give 2-chloro-2-methylbutane as product [Y], CH₃-CH₂-C(Cl)(CH₃)₂ . Nucleophilic substitution of [Y] with alcoholic KCN yields 2,2-dimethylbutanenit