See image — GOC and Organic Chemistry Basics Chemistry Question

💡 Solution & Explanation

Concept: The stability of carbocations (carbonium ions) increases with increasing substitution at the positively charged carbon, due to hyperconjugation and inductive electron-donating effects of alkyl groups. Step 1: Identify the structure of each carbocation. - n-butyl cation (primary): CH3CH2CH2CH2+, the positive charge is on a primary carbon with zero alkyl substituents directly on the cationic carbon. - sec-butyl cation (secondary): CH3CH2CH+(CH3), the positive charge is on a secondary carbon with two alkyl groups stabilizing it. - tert-butyl cation (tertiary): (CH3)3C+, the positive charge is on a tertiary carbon with three alkyl groups stabilizing it. Step 2: Apply the stability order of carbocations. Tertiary > Secondary > Primary > Methyl The tert-butyl cation has three methyl groups donating electron density to the positive carbon via hyperconjugation and inductive effects, making it the most stable among the three options. Step 3: Why other options fail. - (a) sec-butyl is less stable than tert-butyl because it has only two alkyl groups on the cationic carbon. - (c) n-butyl (primary) is the least stable as the cationic carbon bears no alkyl substituents for stabilization. - (d) None of these is incorrect because tert-butyl is indeed a valid and most stable option among those listed. Therefore, the correct answer is B.