CBSE 2023 · Region 5 · Set 1 · Q30 · 3 marks
(i)Why is the $\displaystyle \mathrm{C}-\mathrm{O}$ bond length in phenols less than that in methanol ?(ii)Arrange the following in order of increasing boiling point : Ethoxyethane, Butanal, Butanol, n-butane(iii)How can phenol be prepared from anisole? Give reaction.(i)Give mechanism of the following reaction : $\displaystyle \mathbf{2}+\mathbf{1}=\mathbf{3}$ $\displaystyle \mathrm{CH}_{3} \mathrm{CH}_{2} \mathrm{OH} \xrightarrow[413 \mathrm{~K}]{\mathrm{H}_{2} \mathrm{SO}_{4}} \mathrm{CH}_{3} \mathrm{CH}_{2}-\mathrm{O}-\mathrm{CH}_{2} \mathrm{CH}_{3}+\mathrm{H}_{2} \mathrm{O}$(ii)Illustrate hydroboration - oxidation reaction with an example.
(i)
Why is the $\displaystyle \mathrm{C}-\mathrm{O}$ bond length in phenols less than that in methanol ?
(ii)
Arrange the following in order of increasing boiling point : Ethoxyethane, Butanal, Butanol, n-butane
(iii)
How can phenol be prepared from anisole? Give reaction.
(i)
Give mechanism of the following reaction : $\displaystyle \mathbf{2}+\mathbf{1}=\mathbf{3}$ $\displaystyle \mathrm{CH}_{3} \mathrm{CH}_{2} \mathrm{OH} \xrightarrow[413 \mathrm{~K}]{\mathrm{H}_{2} \mathrm{SO}_{4}} \mathrm{CH}_{3} \mathrm{CH}_{2}-\mathrm{O}-\mathrm{CH}_{2} \mathrm{CH}_{3}+\mathrm{H}_{2} \mathrm{O}$
(ii)
Illustrate hydroboration - oxidation reaction with an example.
Marking-scheme solution
(i) Partial double bond character due to resonance in phenol and no resonance in methanol / \(\displaystyle \mathrm{sp}^{2}\) hybridisation in phenol and \(\displaystyle \mathrm{sp}^{3}\) hybridisation in methanol.
(ii) n-Butane < Ethoxyethane < Butanal < Butanol
(iii) \(\displaystyle \mathrm{C}_{6} \mathrm{H}_{5} \mathrm{OCH}_{3}+\mathrm{HX} \longrightarrow \mathrm{C}_{6} \mathrm{H}_{5} \mathrm{OH}+\mathrm{CH}_{3} \mathrm{X}\)
Alcohols, Phenols and EthersAlcohols and PhenolsApplyshort_answermedium
More from Alcohols, Phenols and Ethers
- In the reaction R-OH+HCl ZnCl 2 RCl+H 2 O, what is the correct order of reactivity of alcohols?2025 · asked 4×
- Write chemical equations for the following reactions: (Do any three) Hydroboration - oxidation reaction…2024 · asked 3×
- What will be formed after oxidation reaction of secondary alcohol with chromic anhydride (CrO 3)?2025 · asked 3×
- Which of the following alcohols will not undergo oxidation?2023 · asked 3×
- Match the reagents required for the given reactions: I. Oxidation of primary alcohols to (p) NaBH 4 aldehydes…2024 · asked 3×
- Assertion: p-nitrophenol is more acidic than phenol. Reason (R): Nitro group is an electron-withdrawing…2026 · asked 3×
- Write the reaction involved in the following: Reimer-Tiemann reaction Kolbe's reaction Friedal-Crafts…2026 · asked 3×
- Write the equations of the reactions involved in the following: (i) Reimer-Tiemann reaction (ii) Kolbe's…2024 · asked 3×
CBSE Class 12 Chemistry past-paper question from the 2023board exam, with the answer as CBSE’s own marking scheme gives it. Where our answers come from.