Structures of methanol, phenol and methoxymethaneमेथेनॉल, फ़ीनॉल और मेथॉक्सीमेथेन की संरचनाएँStructures of methanol, phenol and methoxymethane
NCERT Fig 7.1 · Class 12 Chemistry · Chapter 7 · interactive diagram
Parts and what they mean
- Oxygen of methanol: sp³ with two lone pairs (मेथेनॉल का ऑक्सीजन: sp³, दो एकाकी युग्मों के साथ) — The C–O σ bond forms by overlap of an sp³ orbital of C with an sp³ orbital of O.
- Methyl group (sp³ carbon) (मेथिल समूह (sp³ कार्बन)) — C–O bond length in methanol = 142 pm.
- Hydroxyl H (O–H = 96 pm) (हाइड्रॉक्सिल H (O–H = 96 pm)) — C–O–H angle 108.9°: slightly less than tetrahedral (109°28′) due to repulsion between the lone pairs of O.
- Why the angle is less than 109°28′ (कोण 109°28′ से कम क्यों) — Lone pair–lone pair repulsion is stronger than bond pair repulsion and squeezes the C–O–H angle.
- Benzene ring (sp² carbons) (बेंज़ीन वलय (sp² कार्बन)) — In phenol the –OH is attached to an sp² hybridised ring carbon.
- Oxygen of phenol (फ़ीनॉल का ऑक्सीजन) — Its lone pair is in conjugation with the ring; C–O = 136 pm.
- Hydroxyl H of phenol (C–O–H = 109°) (फ़ीनॉल का हाइड्रॉक्सिल H (C–O–H = 109°)) — This H is far more acidic than in alcohols (pKa 10.0 vs 15.9 for ethanol).
- Why phenol has a shorter C–O bond (136 pm) (फ़ीनॉल में C–O बंध छोटा (136 pm) क्यों) — (i) partial double bond character from conjugation of the O lone pair with the ring; (ii) the carbon is sp² hybridised.
- Ether oxygen: 2 bond pairs + 2 lone pairs, ~tetrahedral (ईथर ऑक्सीजन: 2 बंध युग्म + 2 एकाकी युग्म, लगभग चतुष्फलकीय) — C–O–C = 111.7°.
- Methyl group of methoxymethane (मेथॉक्सीमेथेन का मेथिल समूह) — C–O = 141 pm, almost the same as in alcohols.
- Second methyl group (दूसरा मेथिल समूह) — Both R groups are bulky compared with H.
- Why the ether angle is more than 109°28′ (ईथर कोण 109°28′ से अधिक क्यों) — Repulsive interaction between the two bulky (–R) groups opens the angle slightly.
Original diagram drawn by Simple Learning Hub, based on NCERT Fig 7.1. Report a mistake