Carboxylic Acids

Question 1

Preparation reactions

Answer 1

• oxidation of primary alcohols using a catalyst
• oxidation of aldehydes using a catalyst
• hydrolysis of nitriles, esters or amides

Question 2

Catalysts used in oxidation of primary alcohols and aldehydes to form carboxylic acid

Answer 2

Primary alcohols:
- acidified potassium permanganate
- acidified dichromate
- hot copper(II) oxide

Aldehydes:
- same as above
- Tollens reagent
- Fehling’s solution

Question 3

What is needed for the hydrolysis of nitriles into carboxylic acids?

Answer 3

A dilute acid

Question 4

Reactions

Answer 4

• formation of salts
• condensation reactions
• reduction to form aldehyde and then primary alcohols using lithium aluminium hydride

Question 5

Formation of salts reactions

Answer 5

Metals: carboxylic acid + metal —> salt and hydrogen gas

Metal hydroxide: carboxylic acid + metal hydroxide —> salt + water

Metal oxides: carboxylic acid + metal oxide —> salt + water

Metal carbonates: carboxylic acid + metal carbonate —> salt + water + carbon dioxide

Question 6

Condensation reactions

Answer 6

• react with alcohols to form esters using concentrated sulphuric or phosphoric acid
• react with amines to form amides using heat and neutralisation