What you’ll learn5 learning objectivesChoose one objective for a focused lesson, or study the complete topic.33.1.1Preparation of benzoic acid• Recall preparation of benzoic acid: (a) reaction of an alkylbenzene with hot alkaline KMnO₄ and then dil. acid, exemplified by methylbenzeneSyllabus objective33.1.2Carboxylic acids to acyl chlorides• Describe the reaction of carboxylic acids with PC l ₃ and heat, PCl ₅ or SOCl ₂ to form acyl chloridesSyllabus objective33.1.3Oxidation of carboxylic acids• Recognise that some carboxylic acids can be further oxidised:- (a) the oxidation of methanoic acid, HCOOH, with Fehling’s reagent or Tollens’ reagent or acidified KMnO₄ or acidified K₂Cr₂O₇ to form carbon dioxide and water- (b) the oxidation of ethanedioic acid, HOOCCOOH, with warm acidified KMnO₄ to form carbon dioxideSyllabus objective33.1.4Acidities of carboxylic acids, phenols• Describe/explain: the relative acidities of carboxylic acids, phenols and alcoholsSyllabus objective33.1.5Acidities of chlorine-substituted carboxylic• Describe/explain: the relative acidities of chlorine-substituted carboxylic acidsSyllabus objective