VJC 2025 CAD Tutorial

Victoria Junior College JC 2 Chemistry Tutorial: Carboxylic Acids & Derivatives Complete the following tables. 1. Preparation of carboxylic acids Starting compound Reagents and conditions Product K2Cr2O7(aq), H2SO4(aq), heat under reflux OR KMnO4(aq), H2SO4(aq), heat (CH3)2CHCH2CO2H (CH3)2CHCH2CHO (CH3)2CHCH2CH(CN)OH (CH3)2CHCH2CH(CO2H)OH 2. Reactions of carboxylic acids Starting Compound Reaction Type Reagents and Conditions Organic Product [if any] (CH3)2C(OH)CO2H redox NaOH Na2CO3 HBr(g) heat PCl3 or SOCl2, heat OR PCl5 CH3CH(OH)CH3 conc. H2SO4 heat CH3COCl reduction oxidation

Interconversion of Carboxylic Acids and Acid Derivatives Hydrolysis

Preparation and Reactions of Carboxylic Acids 1 Devise syntheses of the following compounds from the given starting material. Identify the reagents and conditions at each step and draw the structural formulae of the intermediates. (a) CH3CH2CHO → CH3CH2CH(OH)CO2H (2-step synthesis) (b) (CH3)2CHOH → (CH3)2CHCO2H (3-step synthesis) (c) CH3CH2CH2OH → CH3CH2OH (3-step synthesis) (d) (2-step synthesis)

2 Citric acid, which causes the sharp taste of lemon juice, has the following formula. What reacts completely with 1 mol of citric acid? A 3 mol of PCl5 C 4 mol of Na B 4 mol of HCl(g) D 4 mol of NaOH(aq) N13/I/27 3 The small hive beetle, which invades colonies of the honeybee, identifies these colonies by detecting the bees’ own alarm signal, the pheromone 3–methylbutyl ethanoate. How may this ester be made in the laboratory? A (CH3)2CHCH2CO2H + CH3CH2OH → ester + H2O B (CH3)2CHCH2CH2CO2H + CH3OH → ester + H2O C CH3CO2H + (CH3)2CHCH2CH2OH → ester + H2O D CH3CO2H + CH3CH2CH(CH3)CH2OH → ester + H2O Modified N10/I/28 Acidity of Carboxylic Acids 4 In which sequence is it correctly stated that the value of pKa decreases continuously? A CH3CO2H > CCl3CO2H > C2H5OH > C6H5OH B CCl3CO2H > CH3CO2H > C2H5OH > C6H5OH C C2H5OH > C6H5OH > CH3CO2H > CCl3CO2H D C6H5OH > C2H5OH > CH3CO2H > CCl3CO2H

Preparation and Reactions of Acyl Chlorides 5(a)(i) Draw a displayed formula of benzoyl chloride, C 6H5COCl. Describe a pathway in which it can be synthesised from benzoic acid. (ii) Describe three reactions of benzoyl chloride with water, ethanol and methylamine, giving a balanced equation in each case. (b) State and explain how the ease of hydrolysis of 1-chloropropane differ from that of propanoyl chloride and chlorobenzene. Adapted J94/I/8, N23/I/22 ………………………………………………………………………………………………….…… ………………………………………………………………………………………………….…… ……………………………………………………………………………………………………… …………………………………………………………………………………………………….… …………………………