**Assertion (A):** (CH3)3C- (tert-butyl carbanion) is less stable than CH3- (methyl carbanion). **Reason (R):** Alkyl groups have a +I effect that increases electron density on the carbanion carbon, destabilizing it.

**Assertion (A):** Propene is more stable than ethylene. **Reason (R):** Propene has 3 alpha-hydrogen atoms that contribute to hyperconjugation with the pi system, while ethylene has no alpha-hydrogen atoms.

**Assertion (A):** Phenol is more acidic than cyclohexanol. **Reason (R):** The phenoxide ion (C6H5O-) is stabilized by resonance delocalization into the aromatic ring, whereas the cyclohexoxide ion has no such delocalization.

**Assertion (A):** 2-Butene (CH3-CH=CH-CH3) shows geometrical isomerism, but 2-methylpropene (CH3)2C=CH2 does not. **Reason (R):** In 2-methylpropene, one of the doubly-bonded carbons has two identical methyl groups, violating the condition for geometrical isomerism.

**Assertion (A):** Tertiary carbocations are more stable than primary carbocations. **Reason (R):** Alkyl groups have +I effect and contribute to hyperconjugation, both of which stabilize the positive charge.