26.3 - Carboxylic acids

Question 1

What is the carboxyl group?

Answer 1

C=O and O-H

Question 2

What are carboxylic acids and their derivatives used for?

Answer 2

Starting materials in organic synthesis or intermediates in the formation of more useful compounds

Question 3

Describe the trend in solubility of carboxylic acids

Answer 3

• Carboxylic acids with up to four carbon atoms are soluble (C=O and O-H bonds are polar and so can form hydrogen bonds)
• Increasing carbon chain length decreases solubility as the non-polar carbon chain has a greater effect on the overall polarity of the molecule

Question 4

Describe the strength of carboxylic acids

Answer 4

They are classed as weak acids as they partially dissociate when dissolved in water

Question 5

When do carboxylic acids take place in redox and neutralisation reactions?

Answer 5

• Redox: with metals
• Neutralisation: with bases(alkalis, metal oxides, metal hydroxides, and carbonates)

Question 6

What are the products of redox reactions of carboxylic acids with metals? What would you observe?

Answer 6

carboxylate salt and hydrogen gas
- effervescence as hydrogen gas is forming
- metal disappearing

Question 7

What are the products of neutralisation reactions of carboxylic acids with metal oxides?

Answer 7

salt and water

Question 8

What are the products of neutralisation reactions of carboxylic acids with alkalis?

Answer 8

salt and water

Question 9

What are the products of neutralisation reactions of carboxylic acids with carbonates?

Answer 9

salt, water, and carbon dioxide

Question 10

What is the test for the carboxyl group?

Answer 10

The reaction of carboxylic acids with carbonates
- The only commonly organic compounds sufficiently acidic to react with carbonates, phenols aren’t acidic enough to react with carbonates