Review the key concepts, formulae, and examples before starting your quiz.
🔑Concepts
Carboxylic acids are a homologous series of organic compounds characterized by the carboxyl functional group, written as .
The general formula for the carboxylic acid homologous series is . For ethanoic acid, , giving the formula .
Ethanoic acid is a weak acid, meaning it only partially dissociates in aqueous solution: .
Ethanoic acid can be prepared by the oxidation of ethanol using an oxidizing agent like acidified potassium manganate(VII) () or through bacterial oxidation (vinegar production).
Carboxylic acids react with alcohols in the presence of an acid catalyst (usually concentrated ) to form esters and water in a process called esterification.
Ethanoic acid reacts with metals to form a salt (ethanoate) and hydrogen gas, and with carbonates to form a salt, water, and carbon dioxide gas.
📐Formulae
💡Examples
Problem 1:
Write the balanced chemical equation for the reaction between ethanoic acid () and magnesium ().
Solution:
Explanation:
Ethanoic acid reacts with reactive metals like magnesium to produce a salt (magnesium ethanoate) and hydrogen gas. Because the ethanoate ion has a charge of and the magnesium ion has a charge of , two ethanoate ions are required for every magnesium ion.
Problem 2:
Identify the products formed when ethanoic acid reacts with ethanol in the presence of concentrated sulfuric acid.
Solution:
Explanation:
This is an esterification reaction. The hydroxyl group () from the acid and the hydrogen () from the alcohol's functional group combine to form , while the remaining fragments join to form the ester, ethyl ethanoate.