3.3.9 羧酸及其衍生物 (僅A2)：練習題

Which of the following reagents can be used to distinguish between a sample of propan-1-ol and a sample of propanoic acid by the observation of effervescence?

What are the organic products formed when ethyl propanoate is heated under reflux with an excess of aqueous sodium hydroxide?

In the nucleophilic addition-elimination mechanism between ethanoyl chloride and ethylamine, which statement correctly describes the first step of the reaction?

Which of the following correctly identifies the structure of the ester formed by the reaction of propan-2-ol with ethanoic acid in the presence of an acid catalyst?

Ethanoic anhydride is used in preference to ethanoyl chloride in the industrial production of aspirin. Which of the following is a valid reason for this preference?

State a chemical test, including the expected observation, that can be used to distinguish between aqueous propanoic acid and propan-1-ol.

Write a balanced chemical equation for the reaction of propanoic acid with methanol in the presence of a concentrated sulfuric acid catalyst. Use structural formulas for all organic species.

In the nucleophilic addition–elimination reaction between ethanoyl chloride and ammonia, identify the nucleophile and explain why two molar equivalents of ammonia are required to produce ethanamide.

Part (a): Propanoic acid reacts with methanol in the presence of a concentrated sulfuric acid catalyst to form an ester. Write a balanced equation for this reaction using structural formulas and provide the IUPAC name of the ester formed.
Part (b): Esters can be hydrolysed under different conditions. Write a balanced chemical equation for the alkaline hydrolysis of methyl propanoate using aqueous sodium hydroxide.
Part (c): Identify the class of organic compounds, commonly found in vegetable oils and animal fats, that reacts with sodium hydroxide to produce soap and glycerol.

Part (a): Ethanoyl chloride reacts rapidly with nucleophiles. Outline the nucleophilic addition-elimination mechanism for the reaction between ethanoyl chloride, \(CH_{3}COCl\), and an excess of ammonia to form ethanamide. Include all necessary curly arrows, relevant lone pairs, and charges.
Part (b): Explain why the carbon atom in the carbonyl group of an acyl chloride is more susceptible to nucleophilic attack than the carbon atom in a carboxylic acid.
Part (c): In the manufacture of aspirin, salicylic acid (2-hydroxybenzoic acid) is reacted with ethanoic anhydride rather than ethanoyl chloride. State two advantages of using ethanoic anhydride in this industrial process.
Part (d): Biodiesel is produced through the transesterification of vegetable oils. Identify the reagent and the catalyst required for the conversion of a vegetable oil (triglyceride) into biodiesel.