CBSE Class 12 Chemistry 2023 Delhi Set 1 Solved Paper

Question : 30

Total: 35

(a) (i) Why is the C−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.
OR
(b) (i) Give mechanism of the following reaction:
CH3−CH2−OH

H2SO4

─────▸

413K

CH3CH2−O −CH2CH3+H2O
(ii) Illustrate hydroboration - oxidation reaction with an example.

Solution: 👈: Video Solution

(a) (i) C−O bond length in phenol is less than methanol because of presence of benzene ring which is aromatic and consisting of double bond. The lone pair present in oxygen is shared with partial conjugation effect while in methanol the lone pair of oxygen shared with normal carbon atom.
(ii) Butanol > Butane > Butanal > Ethoxy ethane

OR
2CH3−CH2−OH

H2SO4

─────▸

413K

CH3−CH2−O −CH2−CH3+H2O

CH3−CH2−O−CH2−CH3+H2O
(ii) Hydroboration -

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