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Per NCERT §4.5.3 (orbital-overlap directional argument), why does simple overlap of unhybridised C atomic orbitals FAIL to explain methane's 109.5° angle?
A2p orbitals point at random
BC has no 2p electrons
CThree 2p orbitals on C are mutually 90° apart, predicting 90° H-C-H — disagrees with observed 109.5°. Hybridisation resolves this.
DMethane is actually 90°
Answer & Solution
Correct answer: C. Three 2p orbitals on C are mutually 90° apart, predicting 90° H-C-H — disagrees with observed 109.5°. Hybridisation resolves this.
Per NCERT §4.5.3 + 4.6, pure 2p overlap gives 90° (perpendicular axes). Observed 109.5° demands sp³ hybrids that orient tetrahedrally.
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