26.3 - Carboxylic Acids

Question 1

What is a carboxyl group?

Answer 1

COOH (carbonyl + hydroxyl group)

Question 2

Which carbon is always carbon-1 in a carboxylic acid?

Answer 2

The carboxyl carbon

Question 3

Why are carboxylic acids soluble?

Answer 3

The C=O and O-H bonds are polar, allowing carboxylic acids to form hydrogen bonds with water molecules

Question 4

Explain the effect of changing the length of the carbon chain on the solubility of the carboxylic acid

Answer 4

The longer the chain, the lower the solubility. This is because the non-polar carbon chain has a greater effect on the overall polarity of the molecule.

Question 5

Are carboxylic acids strong or weak acids?

Answer 5

Weak acids (only partially dissociate)

Question 6

What reactions can carboxylic acids undergo?

Answer 6

Redox reactions with metals

Neutralisation reactions with bases

Question 7

What is produced when a carboxylic acid reacts with a metal in a redox reaction?

Answer 7

Carboxylate salt + hydrogen gas (H2)

Question 8

What would you observe when a carboxylic acid reacts with a metal in a redox reaction?

Answer 8

The metal would disappear

Effervescence

Question 9

What bases do carboxylic acids react with?

Answer 9

Metal oxides
Carbonates
Alkalis

Question 10

Carboxylic acid + metal oxide = ?

Answer 10

Salt + Water

Question 11

Carboxylic acid + alkali = ?

Answer 11

Salt + Water

Question 12

Carboxylic acid + carbonate = ?

Answer 12

Salt + Water + Carbon dioxide

Question 13

How could you distinguish between a carboxylic acid and a phenol?

Answer 13

Phenols wouldn’t react in a neutralisation reaction with carbonates because they aren’t acidic enough