Organic Chemistry: Carboxylic Acids

Question 1

What is the general formula of carboxylic acids?

Answer 1

CnH2n+1COOH

Question 2

What is the functional group of carboxylic acids?

Answer 2

COOH

Question 3

What are the properties of ethanoic acid? (3)

Answer 3

Weak acid
high pH
low dissociation

Question 4

How is ethanoic acid formed? (2)

Answer 4

Oxidation of ethanol:

• in air
• by fermentation with acidified potassium permanganate

Question 5

What are acetobacter?

Answer 5

bacteria naturally present in air

Question 6

What happens when we leave a solution of ethanol exposed to air?

Answer 6

Enzymes from the bacterium speed up the conversion of ethanol to ethanoic acid

Question 7

What does the oxidation of ethanol in air not take place without?

Answer 7

does not take place in the absence of oxygen

Question 8

What is the word equation for the oxidation in air of ethanol to ethanoic acid?

Answer 8

ethanol + oxygen => ethanoic acid + water

Question 9

What is the symbol equation for the oxidation in air of ethanol to ethanoic acid?

Answer 9

C2H5OH + 2[O] → CH3COOH + H2O

Question 10

Why do we write [O]?

Answer 10

the oxidation reaction is complicated but oxygen is involved

Question 11

Describe the oxidation in air of ethanol to ethanoic acid (3)

Answer 11

1. Solution of ethanol is exposed to air
2. Bacterium speed up conversion of ethanol to ethanoic acid
   ( C2H5OH + 2[O] → CH3COOH + H2O )
3. Reaction makes vinegar, vinegar is solution of ethanoic acid

Question 12

Describe the oxidation of ethanol with acidified potassium manganate (VII)

Answer 12

1. Heat ethanol with potassium manganate and sulfuric acid in a flask with a condenser in an upright position (refluxing)
   C2H5OH + 2[O] → CH3COOH + H2O
2. Ethanoic acid is formed

Question 13

Why do we use a condenser in the oxidation of ethanol with acidified potassium manganate (VII)?

Answer 13

Alcohol is volatile - prevents escaping