Alcohols

Question 1

What are alcohols?

Answer 1

-Organic compounds with the functional group -OH
-May be one or more of these functional groups in a molecule

Question 2

Prefix

Answer 2

-Hydroxy- (where higher priority group gives suffix)

Question 3

Suffix

Answer 3

-ol

Question 4

How can alcohols be classified?

Answer 4

-Alcohols may be classified as:
-Primary
-Secondary
-Tertiary

Question 5

What determines the classification?

Answer 5

-The number of alkyl groups joined to the C bonded to the hydroxyl group

Question 6

What does [O] indicate?

Answer 6

Oxidising agent

Question 7

Why do alcohols start to “go off”/become acidic?

Answer 7

Because the oxygen in the air will oxidise them over time

Question 8

What is the oxidising agent used in the lab?

Answer 8

-Acidified potassium dichromate
-K2Cr2O7 /H2SO4(aq)

Question 9

Half equation for dichromate(VI) ions as an oxidising agent

Answer 9

Cr2O7 2- +14H+ +6e- —> 2Cr3+ +7H2O

Question 10

What is the colour change in this reaction?

Answer 10

Orange to green

Question 11

What will primary alcohols oxidise to?

Answer 11

Aldehydes

Question 12

What is the general equation for primary alcohol oxidation?

Answer 12

RCH2OH + [O] —> RCHo + H2O

-Distilled immediately with K2Cr2O7

Question 13

Why is the aldehyde distilled

Answer 13

To prevent it forming a carboxylic acid

Question 14

Why is a thermometer used for this reaction?

Answer 14

-To measure the boiling point of the product passing into the condenser
-Ensures you are boiling the aldehyde off not the alcohol

Question 15

Primary alcohols to carboxylic acids equation