Unit 2 Soaps, Detergents and Emulsions

Question 1

How are soaps produced

Answer 1

Alkaline hydrolysis of edible fats and oils
Hydrolysis produces 3 fatty acid molecules and 1 glycerol

Question 2

Saponification

Answer 2

Fatty acid molecules neutralised by alkali, forming water soluble ionic salts called Soaps

Question 3

Cleaning action of soap

Answer 3

Soap has both hydrophobic (oil) soluble tail and hydrophilic (water) soluble head
Miscelles begin to form by agitation
Miscelles become repulsed due to the negatively charged heads

Question 4

What is formed when soap is used in hard water

Answer 4

Scum is formed which is an insoluble precipitate

Question 5

How to recognise hard water

Answer 5

Cloudy
Limescales in kettles
Lack of foam from soap

Question 6

Soapless detergents

Answer 6

Ionic hydrophilic head
Doesn’t form scum

Question 7

Emulsifier

Answer 7

Prevent non-polar and polar liquids from separating into layers

Question 8

How can you make Emulsifiers

Answer 8

Reacting edible oils with glycerol