Q10 / 75 · JEE Main 2026 (23 January Shift 2) · Chemistry
Given below are two statements:
Statement I: $\left(\mathrm{CH}_{3}\right)_{3} \stackrel{\oplus}{\mathrm{C}}$ is more stable than $\stackrel{\oplus}{\mathrm{C}} \mathrm{H}_{3}$ as nine hyperconjugation interactions are possible in $\left(\mathrm{CH}_{3}\right)_{3} \stackrel{\oplus}{\mathrm{C}}$.
Statement II: $\stackrel{\oplus}{\mathrm{C}} \mathrm{H}_{3}$ is less stable than $\left(\mathrm{CH}_{3}\right)_{3} \stackrel{\oplus}{\mathrm{C}}$ as only three hyperconjugation interactions are possible in $\stackrel{\oplus}{\mathrm{C}} \mathrm{H}_{3}$.
In the light of the above statements, choose the correct answer from the options given below
Statement I: $\left(\mathrm{CH}_{3}\right)_{3} \stackrel{\oplus}{\mathrm{C}}$ is more stable than $\stackrel{\oplus}{\mathrm{C}} \mathrm{H}_{3}$ as nine hyperconjugation interactions are possible in $\left(\mathrm{CH}_{3}\right)_{3} \stackrel{\oplus}{\mathrm{C}}$.
Statement II: $\stackrel{\oplus}{\mathrm{C}} \mathrm{H}_{3}$ is less stable than $\left(\mathrm{CH}_{3}\right)_{3} \stackrel{\oplus}{\mathrm{C}}$ as only three hyperconjugation interactions are possible in $\stackrel{\oplus}{\mathrm{C}} \mathrm{H}_{3}$.
In the light of the above statements, choose the correct answer from the options given below
- AStatement I is false but Statement II is true
- Correct answerBStatement I is true but Statement II is false
- CBoth Statement I and Statement II are true
- DBoth Statement I and Statement II are false
Solution
Statement I: In the tert-butyl carbocation $(CH_3)_3C^+$, there are three methyl groups attached to the carbocationic carbon. Each methyl group has 3 $\alpha$-hydrogens, making a total of 9 $\alpha$-hydrogens. Thus, 9 hyperconjugation interactions are possible, which significantly stabilize the carbocation. Statement I is true.
Statement II: In the methyl carbocation $CH_3^+$, there are no $\alpha$-carbons and consequently no $\alpha$-hydrogens. Hyperconjugation requires the presence of at least one $\alpha$-hydrogen on a carbon adjacent to the $sp^2$ hybridized carbocation center. Therefore, zero hyperconjugation interactions are possible in $CH_3^+$. Statement II is false because it claims three hyperconjugation interactions are possible.
Conclusion: Statement I is true but Statement II is false.
Statement II: In the methyl carbocation $CH_3^+$, there are no $\alpha$-carbons and consequently no $\alpha$-hydrogens. Hyperconjugation requires the presence of at least one $\alpha$-hydrogen on a carbon adjacent to the $sp^2$ hybridized carbocation center. Therefore, zero hyperconjugation interactions are possible in $CH_3^+$. Statement II is false because it claims three hyperconjugation interactions are possible.
Conclusion: Statement I is true but Statement II is false.
Hence, the correct answer is option: 'B'.