Chemistry Class 12 NCERT Solutions: Chapter 11 Alcohols Phenols and Ethers Part 14 (For CBSE, ICSE, IAS, NET, NRA 2022)

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Q: 8. Ortho and para nitrophenols are more acidic than phenol. Draw the resonance structures of the of the corresponding phenoxide ions

Answer:

Q_8_1_The Resonance Structure of the Phenoxide Ion

Resonance structure of the phenoxide ion

Q_8_2_Resonance Structures of P-Nitrophenoxide Ion

Resonance structures of p-nitrophenoxide ion

Q_8_3_Resonance Structures of M-Nitrophenoxide Ion

Resonance structures of m-nitrophenoxide ion

It can be observed that the presence of nitro groups increases the stability of phenoxide ion.

Q: 9. Write the equations involved in the following reactions:

(i) Reimer-Tiemann reaction

(ii) Kolbe՚s reaction

Answer:

(i) Reimer- Tiemann Reaction

Q_9_i_ Reimer- Tiemann Reaction

(ii)

Kolbe՚s reaction

Q_9_i_ Kolbe՚s Reaction

Q: 10. Write the reactions of Williamson synthesis of 2-ethoxy-3-methylpentane starting from ethanol and 3-methylpentan-2-ol.

Answer:

In Williamson synthesis, an alkyl halide reacts with an alkoxide ion. Also, it is an reaction. In the reaction, alkyl halides should be primary having the least steric hindrance. Hence, an alkyl halide is obtained from ethanol and alkoxide ion from 3- methylpentane-2-ol.

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Q: 11. Which of the following is an appropriate set of reactants for the preparation of 1-Methoxy-4-nitrobenzene and why?

(i)

Q_11_i_Appropriate Set of Reactants

(ii)

Q_11_ii_Appropriate Set of Reactants

Answer:

Set (ii) is an appropriate set of reactants for the preparation of 1-methoxy-4 nitrobenzene.

Q_11_Ans_Appropriate Set of Reactants

In set (i) , sodium methoxide is a strong nucleophile as well as a strong base. Hence, an elimination reaction predominates over a substitution reaction.

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