3.3.5. Alcohols

Question 1

What is an alcohol?

Answer 1

An organic compound with an -OH group

Question 2

What are the physical properties of alcohols?

Answer 2

Relatively high mp and bp, miscible with water

Question 3

Explain the physical properties of alcohols

Answer 3

OH group leads to hydrogen bonding

Question 4

What are the two methods for production of ethanol?

Answer 4

Fermentation of glucose, hydration of ethene

Question 5

What are the conditions for the production of ethanol from ethene?

Answer 5

Heat, sulphuric acid catalyst, water

Question 6

What conditions are necessary for the fermentation of glucose?

Answer 6

Compromise temperature of 35 degrees celcius, enzymes, sealed vessel

Question 7

Give two advantages of production of ethanol from glucose

Answer 7

Low tech required, renewable, potentially carbon neutral

Question 8

Give three disadvantages of production of ethanol from glucose

Answer 8

Slow, Low yield, Significant land use, Has to be distilled, Labour intensive

Question 9

How is ethanol extracted after fermentation of glucose?

Answer 9

Fractional distillation

Question 10

Give two advantages of production of ethanol from ethene

Answer 10

Fast reaction, Pure product, Continuous process, Low on manpower, High yield, 100% alcohol

Question 11

Give three disadvantages of production of ethanol from ethene

Answer 11

High technology, Non-renewable source, Expensive equipment

Question 12

What is the product of dehydration of an alcohol?

Answer 12

An alkene

Question 13

What conditions are necessary for dehydration of an alcohol?

Answer 13

Conc. phosphoric/sulphuric acid catalyst, heat and reflux

Question 14

What can primary alcohols be oxidized to?

Answer 14

Aldehydes and carboxylic acids

Question 15

What can secondary alcohols be oxidized to?

Answer 15

Ketones

Question 16

What can tertiary alcohols be oxidized to?

Answer 16

Nothing

Question 17

How is oxidation symbolized in an equation?

Answer 17

[O]

Question 18

What reagent is used for the oxidation of alcohols?

Answer 18

Acidified potassium dichromate

Question 19

What colour change is observed in the oxidation of alcohols?

Answer 19

Acidified potassium dichromate turns green from orange

Question 20

Which experimental method is used to convert alcohols to carboxylic acids?

Answer 20

Reflux

Question 21

Which experimental method is used to convert alcohols to aldehyde?

Answer 21

Distillation

Question 22

Which chemical tests can distinguish between aldehydes and ketones?

Answer 22

Tollens’s reagent or Fehling’s solution

Question 23

What is observed when Tollens’ reagent is added to aldehydes?

Answer 23

Silver mirror

Question 24

What is observed when Fehling’s solution is added to aldehydes?

Answer 24

Orange precipitate