Markovnikov addition and nitrile hydrolysis sequence Steps: - 3-Methylbut-2-ene ((CH3)2C=CHCH3) reacts with HBr via electrophilic addition; H adds to C3 (more hydrogens), Br to C2, forming tertiary bromide (CH3)2C(Br)CH2CH3 as X. - X reacts with KCN in ethanol via substitution, replacing Br with CN to give (CH3)2C(CN)CH2CH3 as Y. - Acid hydrolysis of Y converts the nitrile group to COOH, extending the chain to (CH3)2C(COOH)CH2CH3 as Z. - Z is named as 2,2-dimethylbutanoic acid based on the longest chain from COOH to ethyl with geminal methyls at C2. Why A is correct: - The product structure COOH-C(CH3)2CH2CH3 follows Markovnikov's rule, where H adds to the less substituted alkene carbon, yielding a tertiary halide that retains branching in the final acid. Why the others are wrong: - B: Requires methyl branching at C3, which would arise from non-Markovnikov addition or different alkene isomer. - C: Implies a straight pentane chain with one methyl at C2, ignoring the tertiary structure from the original alkene. - D: Suggests methyl at C3 in a pentanoic chain, mismatched with the gem-dimethyl from C2 carbocation. Final …