Alcohol

Question 1

What is the functional group of alcohols?

Answer 1

-OH functional group.

Question 2

What is the general formula of alcohols?

Answer 2

CnH2n+1OH

Question 3

How can ethanol be oxidised?

Answer 3

Burning in air/oxygen (complete combustion).
Microbial oxidation - reaction with oxygen in air to form ethanoic acid,
Heating with potassium dichromate (vi) in dilute sulfuric acid to form ethanoic acid - orange - to green

Question 4

Describe the manufacture of ethanol by steam?

Answer 4

React ethane with steam in presence of phosphoric acid catalyst at temperature of 300 Celsius & 60-70 atmospheres - forms ethanol.

Question 5

Describe the manufacture of ethanol by fermentation?

Answer 5

Fermentation of glucose - in absence of air - at temperature of 30 Celsius - using enzymes in yeast as a catalyst - forms ethanol.

Question 6

Why does glucose fermentation occur in the absence of air & at optimum temperature.

Answer 6

Absence of air - oxygen converts ethanol to ethanoic acid - anaerobic respiration.
Optimum temperature - lower temperatures reaction slows & higher temperatures enzymes denature.

Question 7

What are advantages & disadvantages of producing ethanol by steam?

Answer 7

Advantages - cheap.
Disadvantages - non-renewable resource.

Question 8

What are advantages & disadvantages of producing ethanol by fermentation?

Answer 8

Advantage - renewable resource.
Disadvantage - needs to be distilled to increase strength & be purified.