c6.2.4 carboxylic acids

Question 1

what do they form

Answer 1

homologous series

Question 2

what is its functional group

Answer 2

the carboxyl group (-COOH)

Question 3

what do carboxylic acids end in

Answer 3

‘anoic’

Question 4

4 carboxylic acids

Answer 4

methanoic acid (HCOOH)
ethanoic acid (CH3COOH)
propanoic acid (C2H5COOH)
butanoic acid (C3H7COOH)

Question 5

what is the one thing to notice about drawing their displayed formulas

Answer 5

There is a C=O double bond

Question 6

how are they made

Answer 6

formed when alcohols react with an oxidising agent such as potassium manganate (VII) solution

Question 7

explain how carboxylic acids are made (practical)

Answer 7

1. get a tube of ethanol
2. add some oxidising agent (potassium manganate (VII) solution acidified with dilute sulfuric acid) and heat it up in a water bath

Question 8

what happens in the experiment?

Answer 8

colour change occurs because originally, potassium manganate (VII) ions are purple. But then when they are reduced, they change to very pale pink manganate(II) ions

Question 9

Precautions during this experiment

Answer 9

Wear goggles
Take care while stirring because the reaction is violent
Ethanol is flammable
potassium manganate (VII) solution is harmful and will stain skin and clothes

Question 10

general formula for carboxylic acids

Answer 10

C(n) H(2n+1) COOH