Reactions and uses of esters

Question 1

Why are esters used in the food industry?

Answer 1

They have a sweet smell

Question 2

What makes esters good solvents?

Answer 2

They are polar liquids and evaporate easily

Question 3

Why are esters added to plastics?

Answer 3

To make them more flexible

Question 4

What are the two types of hydrolysis?

Answer 4

Acid

Base

Question 5

What is the equation for acid hydrolysis?

Answer 5

Ester + water -> carboxylic acid + alcohol

Question 6

During acid hydrolysis what do you have to do to the ester?

Answer 6

Reflux with dilute acid such as HCl or sulfuric acid

Question 7

During base hydrolysis, what do you have to do to the ester?

Answer 7

Reflux with a dilute alkali such as NaOH

Question 8

What is the equation for base hydrolysis?

Answer 8

Ester + OH- -> carboxylate ion + alcohol

Question 9

What is the product in both types of hydrolysis?

Answer 9

Alcohol

Question 10

What are the two types of fatty acids?

Answer 10

Saturated

Unsaturated

Question 11

What type of carbon carbon bonds do saturated fatty acids have?

Answer 11

Single

Question 12

What type of carbon carbon bonds do unsaturated fatty acids have?

Answer 12

Double

Question 13

Why are van Der waal forces stronger in saturated fatty acids compared to unsaturated fatty acids?

Answer 13

They can fit closer together

Question 14

When you hydrolyse a fat/oil with sodium hydroxide, what are the products?

Answer 14

Glycerol and sodium salt (soap)

Question 15

How is biodiesel produced from vegetable oils?

Answer 15

Reacted with methanol, using a strong alkali catalyst to get a mixture of methyl esters of long chain esters (biodiesel)

Question 16

Is biodiesel 100% carbon neutral?

Answer 16

Energy is used to make the fertiliser to grow the crops and if this energy comes from fossil fuels then the process won’t be carbon neutral