Carboxylic acids and derivatives：練習問題

Which reaction produces propanoic acid as one of the organic products?

An organic compound \(\mathbf{X}\) has the molecular formula \(\text{C}_5\text{H}_{10}\text{O}_2\).

\(\mathbf{X}\) exhibits the following properties:
1. It reacts with aqueous sodium carbonate to produce a gas that turns limewater cloudy.
2. It exists as a pair of non-superimposable mirror images (enantiomers).

Compound \(\mathbf{X}\) is treated with acidified potassium dichromate(\(\text{VI}\)) and heated under reflux, but no colour change is observed.

What is the systematic IUPAC name of compound \(\mathbf{X}\)?

A sample of ethanoic acid, \(\text{CH}_3\text{COOH}\), is treated separately with three different reagents: solid magnesium, solid sodium carbonate, and aqueous sodium hydroxide.

Which row correctly identifies the gas evolved in each reaction?

A hydroxycarboxylic acid \(\mathbf{Z}\) has the formula \(\text{HO}-\text{CH}_2-\text{CH}_2-\text{COOH}\). Under suitable conditions with an acid catalyst, molecules of \(\mathbf{Z}\) can react with each other via esterification to form a cyclic diester with the formula \(\text{C}_6\text{H}_8\text{O}_4\).

How many atoms form the heterocyclic ring of this cyclic diester?

An organic compound \(\mathbf{X}\) has the molecular formula \(\text{C}_4\text{H}_8\text{O}_2\). When \(\mathbf{X}\) is heated under reflux with dilute sulfuric acid, two organic compounds \(\mathbf{Y}\) and \(\mathbf{Z}\) are formed. Compound \(\mathbf{Y}\) reacts with sodium carbonate to produce carbon dioxide gas. Compound \(\mathbf{Z}\) can be oxidised by acidified potassium dichromate(VI) to produce \(\mathbf{Y}\).

What is the systematic name of compound \(\mathbf{X}\)?

State the reagents and conditions required to hydrolyse ethyl propanoate to produce propanoic acid, and write a balanced equation for this reaction.

Propanoic acid is a typical carboxylic acid.
(a) Write a balanced chemical equation for the reaction of propanoic acid with sodium carbonate, \(Na_{2}CO_{3}\), including state symbols.
(b) Identify the organic product formed when propanoic acid is reduced by \(LiAlH_{4}\).
(c) Describe how you would test the gas evolved in part (a) to confirm its identity.