See image — Hydrocarbons Chemistry Question

💡 Solution & Explanation

Concept: Hyperconjugation involves the overlap of C-H sigma bonding orbitals with an adjacent vacant p-orbital (or pi system). The number of C-H bonds available for hyperconjugation equals the number of hydrogen atoms on the carbon(s) directly adjacent (alpha) to the carbocation center. Step 1: Draw the ethyl carbocation. The ethyl carbocation is CH3-CH2+. The positive charge (vacant p-orbital) resides on the terminal carbon (C1, the carbocationic carbon). Step 2: Identify the carbon adjacent to the carbocation center. The only carbon adjacent to the positively charged carbon (C1) is the methyl carbon (C2), which is CH3. Step 3: Count the C-H bonds on the adjacent carbon available for hyperconjugation. The CH3 group has 3 C-H bonds. Each of these sigma bonds can align with and overlap into the vacant p-orbital on the adjacent carbocationic carbon. Step 4: Evaluate why other options fail. - (a) 0: Incorrect, because hyperconjugation does occur in ethyl carbocation. - (c) 5: Incorrect, this would imply all C-H bonds in the molecule participate, but only adjacent C-H bonds overlap with the vacant p-orbital. - (d) 6: Incorrect, ethyl carbocation only has 5 total C-H bonds (3 on CH3 and 2 on CH2+), and the C-H bonds on the carbocationic carbon itself do not overlap with the vacant p-orbital in the same hyperconjugative sense. Only the 3 C-H bonds of the CH3 group (alpha carbon) are available for overlap with the vacant p-orbital on the carbocationic carbon. Therefore, the correct answer is B.