Alcohols

Question 1

What is the functional group of alcohols

Answer 1

-OH

Question 2

What is the general formula for alcohols

Answer 2

Cn H2n+1 OH

Question 3

What happens when something is oxidised?

Answer 3

Gains oxygen

Question 4

Alcohols can be oxidised to form what?

Answer 4

Carboxylic acid

Question 5

Give an example of an oxidising agent that is used to oxidise alcohols

Answer 5

Potassium dichromate (VI) in dilute sulfuric acid

Question 6

Show the displayed formula of ethanol when its heated with acidified potassium dichromate

Answer 6

H H
I I
H - C - C - H -O -H
I I
H H
Potassium dichromate (VI)/sulfuric acid
——————————>
H O
I II
H - C - C
I I
H O - H

Question 7

Potassium dichromate (VI)/sulfuric acid
Ethanol ——————————> ?
Heat

Answer 7

Ethanoic acid

Question 8

What is the colour change when ethanol reacts with acidified potassium dichromate (VI) and why?

Answer 8

Potassium dichromate (VI) changes form orange to green as it oxidises the alcohol

Question 9

Some microorganisms are able to use alcohols as what and what is the process

Answer 9

Microbial Oxidation
- as an energy source
- they use oxygen in the air to oxidise alcohols
- carboxylic acids are made as a by-product
- e.g. oxidation of ethanol produces ethanoic acid

Question 10

What happens to alcohols when they undergo complete combustion and what are the products of this reaction?

Answer 10

• when alcohols are burnt in enough oxygen —> undergo complete combustion
• products : water and carbon dioxide
• alcohol is oxidised

Question 11

Give an example with the name and formula equation of a alcohol oxidation reaction?

Answer 11

Ethanol (C2H5OH) + oxygen (3O2) —> carbon dioxide (2CO2) + water (3H2O)