Carboxylic Acids

Question 1

what are carboxylic acids?

Answer 1

carboxylic acids are a homologous series of compounds that all have “-COOH” as a functional group

Question 2

methanoic acid

Answer 2

HCOOH

Question 3

ethanoic acid

Answer 3

CH3COOH

Question 4

propanoic acid

Answer 4

CH3CH2COOH

Question 5

butanoic acid

Answer 5

CH3CH2CH2COOH

Question 6

what do carboxylic acids react to form?

Answer 6

SALTS (like any other acid)

• the salts formed end in -anoate
• e.g. methanoic acid will form a methanoate, ethanoic acid an ethanoate etc

Question 7

what do aqueous carboxylic acids react with metal carbonates to form?

Answer 7

• a salt, water and carbon dioxide.

- e.g. ethanoic acid + sodium carbonate -> sodium ethanoate + water + carbon dioxide

Question 8

what do aqueous carboxylic acids react with metals to form?

Answer 8

• a salt and hydrogen

- e.g. ethanoic acid + magnesium -> magnesium ethanoate + hydrogen

Question 9

what are carboxylic acids also used for?

Answer 9

• used in the preparation of esters.

- they react with alcohols in the presence of an acid catalyst to form esters.

Question 10

what does vinegar contain?

Answer 10

• A CARBOXYLIC ACID
• ethanoic acid can be made by oxidising ethanol. Microbes, like yeast, cause the ethanol to ferment.
• ethanol can also be oxidised using oxidising agents.
• ethanol + oxygen -> ethanoic acid + water
• ethanoic acid can then be dissolved in water to make vinegar, which is used in flavouring and preserving food.