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Answer the following.

Write chemical equations to illustrate the following name reactions: (1) Williamson’s synthesis…

Chemistry20205 marksReaction
(i)[3.0]
Write chemical equations to illustrate the following name reactions: (1) Williamson’s synthesis. (2) Esterification reaction (3) Reimer-Tiemann reaction.
(ii)[2.0]
Identify the compounds A and B in the given reactions: (1) $\text{C}_2\text{H}_5\text{OH} \xrightarrow[\Delta]{\text{Cu}} \text{A} \xrightarrow{\text{dil. NaOH}} \text{B}$ (2) $\text{C}_6\text{H}_5\text{OH} \xrightarrow{\text{Zn dust}} \text{A} \xrightarrow[\text{anhy. AlCl}_3]{\text{CH}_3\text{COCl}} \text{B}$

Answer

Answer (i)

AI

Equations: $\mathrm{C_{2}H_{5}ONa} + \mathrm{C_{2}H_{5}Cl} \xrightarrow{\text{heat}} \mathrm{C_{2}H_{5}OC_{2}H_{5}} + \mathrm{NaCl}$ $\mathrm{CH_{3}COOH} + \mathrm{C_{2}H_{5}OH} \xrightarrow{\text{conc.}\text{ }\mathrm{H_{2}SO_{4}}\text{,}\text{ }\text{heat}} \mathrm{CH_{3}COOC_{2}H_{5}} + \mathrm{H_{2}O}$ $\mathrm{C_{6}H_{5}OH} + \mathrm{CHCl_{3}} + 3\mathrm{NaOH} \xrightarrow{\text{aq.}\text{ }\text{NaOH}\text{,}\text{ }\text{340}\text{ }\text{K}\text{,}\text{ }\text{then}\text{ }\text{H+}} \mathrm{C_{6}H_{4}(OH)CHO} + 3\mathrm{NaCl} + 2\mathrm{H_{2}O}$

Products: diethyl ether, ethyl ethanoate, salicylaldehyde

1. Williamson's synthesis: sodium ethoxide with chloroethane gives diethyl ether. 2. Esterification: acetic acid with ethanol gives ethyl ethanoate. 3. Reimer-Tiemann reaction: phenol with chloroform and aqueous NaOH gives salicylaldehyde.

Answer (ii)

AI

1A - ethanal: CH3CHO

1B - 3-hydroxybutanal: CH3CH(OH)CH2CHO

2A - benzene: C6H6

2B - 1-phenylethan-1-one: C6H5COCH3

1. A = ethanal ($\mathrm{CH_3CHO}$); B = 3-hydroxybutanal ($\mathrm{CH_3CH(OH)CH_2CHO}$, aldol) 2. A = benzene ($\mathrm{C_6H_6}$); B = acetophenone ($\mathrm{C_6H_5COCH_3}$, Friedel-Crafts acylation)
Phenols

From ISC 2020 Chemistry Paper 1, question 18(b).

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