Question

Consider the following carbocations: (A) $\text{CH}_3\text{C}^+\text{H}_2 \rightarrow \text{B} \rightarrow \text{CH}_3-\text{C}^+\text{H}-\text{CH}_3 \rightarrow \text{C} \rightarrow (\text{CH}_3)_3\text{C}^+$. Statement-I : B is more stable due to $9\alpha H$. Statement-II: A is less stable due to $3\alpha H$.

• A. Statement-I and Statement-II both are correct
• B. Statement-I is incorrect Statement-II is correct
• C. Statement-I is correct Statement-II is incorrect
• D. Statement-I and Statement-II both incorrect

Hint:

Carbocation stability is directly proportional to the number of hyperconjugation structures possible, which equals the number of $\alpha$-hydrogens. The order of stability is $3^\circ>2^\circ>1^\circ>\text{Methyl}$.

Answer 1

The Correct Option is C

Step 1: Carbocation stability depends on hyperconjugation and number of $\alpha$-hydrogens. Step 2: Count $\alpha$-hydrogens: \[ A: 3\alpha H,\quad B: 6\alpha H,\quad C: 9\alpha H \] Step 3: Stability order: \[ \text{Primary}<\text{Secondary}<\text{Tertiary} \] Step 4: Statement I refers to higher stability due to more $\alpha$-hydrogens, which is correct. Step 5: Statement II says fewer $\alpha$-hydrogens cause instability, but $\alpha$-hydrogens actually increase stability. Hence, Statement I is correct and Statement II is incorrect.