CBSE Class 12 Chemistry 2023 Outside Delhi Set 1 Solved Paper

Question : 26 of 35

Marks: +1, -0

SECTION - C

(a) (i) Write the mechanism of the following reaction:

2 {CH}_3 {CH}_2 {OH} {──── ▸}↙{413 {K}}↖{{{H}} }{CH}_3-{CH}_2

-{O}-{CH}_2 -{CH}_3+{H}_2 {O}

(ii) Why ortho-nitrophenol is steam volatile while para-nitrophenol is not?
OR
(b) What happens when
(i) Anisole is treated with

{CH}_3 {Cl}

anhydrous

{AlCl}_3

?
(ii) Phenol is oxidised with

{Na}_2 {Cr}_2 {O}_7 \/ {H}^{+}

?
(iii)

({CH}_3)_3 {C}-{OH}

is heated with

{Cu} \/ 573 {K}

?
Write chemical equation in support of your answer.

Solution:

Option (a) is correct
(i) Mechanism : Follows

{S}_{{N}} 2

Mechanism
Step I :

Step II :

Step III :

{CH}_3 {CH}_2-{{O}} ↖{+}↙{|}↙{H}-{CH}_2 {CH}_3 {──── ▸}

{CH}_3 {CH}_2-{O}-{CH}_2 {CH}_3+{H}^{+}

(ii) Para-nitro phenol has higher boiling point than ortho-nitrophenol due to intermolecular hydrogen bonding present in para-nitrophenol, which require more energy to break these bonds during boiling. In o-nitrophenol intramolecular hydrogen bonding is present to greater extent. Thus o-nitrophenol is stream volatile due to low boiling point.
[OR]
b(i) Friedel craft Alkylation reaction will take place.

(ii) A conjugated diketone is produced Benzoquinone,

(iii) Dehydration takes place and alkene is formed.

{CH}_3 {OH} {──── ▸}↙{573 {K}}↖{{{Cu}} } {HCHO}

R-C↙{|}↙{OH}H-R'{──── ▸}↙{573 {K}}↖{{{Cu}} }\ R-C↙{∥ }↙{O}-R"

Go to Question:

Prev Question

Next Question