3.3.5 Alcohols

Question 1

Define term carbon neutral

Answer 1

An activity which has no net carbon emission to the atmosphere

Question 2

The solution stays blue NO OBSERVABLE REACTION must say to get mark

Question 3

How to identify primary, secondary and tertiary alcohols

Answer 3

Primary - the carbon the OH group is bonded to is bonded to one other carbon
Secondary- the carbon the OH is bonded to is bonded to 2 other carbons
Tertiary - 3 other carbons etc

Question 4

Solubility of alchols

Answer 4

Solubility
But the longer the hydrocarbon chain the less soluable

Question 5

Volatitly of alcohol

Answer 5

Low

Question 6

Boiling point alcohols

Answer 6

The bigger the molecule the more van der waals so the greater the boiling point

Question 7

Uses of alcohol

Answer 7

Disinfectant
Drinks
Anti-freeze

Question 8

What does dehydration of alchol do / produce

Answer 8

Elimination of a water molecule
Produces alkene

Question 9

Dehydration of alcohol catalyst

Answer 9

CONCENTRATED Acid catalyst
Sulfuric acid
E.g. posphoric acid

Question 10

Equasion dehydration of ethanol

Answer 10

Ethanol –> Ethene + water

Question 11

What two methods produce alcohols and give a brief overview

Answer 11

Hydration - alkenes in presence of acid catalysts (phosphoric acid) at high temperature and pressure.
Fermentation- glucose and yeast = carbon dioxide and ethanol

Question 12

How is alcohol dehydrated and why

Answer 12

Distillation
To remove impurities

Question 13

Primary alcohols oxides to …

Answer 13

Aldehydes and the carboxylic acids

Question 14

Secondary alcohol oxides to …

Answer 14

Ketones

Question 15

Which has higher naming priority alcohols or ketones and aldehydes

Answer 15

Ketones and aldehydes
Alcohol or hydroxyl
E.g. 3 hydroxypropanal

Question 16

Are alcohols soluble in water

Answer 16

Yes because it forms hydrogen bonds with water

Question 17

Are alkanes soluble in water

Answer 17

No
Non-polar molecules and can’t form hydrogen bonds

Question 18

What oxidising agent is used to oxide alcohols

Answer 18

Acidified potassium dichromate

Question 19

Why and how is the aldehyde removed

Answer 19

Will easily oxides further
Can be removed by distillation as it has much lower boiling point

Question 20

How can be ensure that all the alcohol is oxidised

Answer 20

Use an excess of the oxidising agent

Question 21

How to remove oxides aldehydes aka carboxylic acid

Answer 21

Heat under reflux

Question 22

How to separate carboxylic acid from impurities

Answer 22

Distillation

Question 23

What type of mechanism is dehydration of alcohol

Answer 23

Elimination

Question 24

Equation for formation of halogen alkane from alcohol

Answer 24

Alcohol + sodium halide + acid —> haloalkane + water + sodium acid

Question 25

Fermentation of alcohol

Answer 25

Yeast in ANAEROBIC conditions Produces ethanol and CO2

Question 26

How is pure ethanol obtained from fermentation

Answer 26

Fractional distillation

Question 27

Which uses milder conditions hydration or fermentation

Answer 27

Fermentation

Question 28

Which produces purer ethanol fermentation or hydration

Answer 28

Hydration

Question 29

In a reflux reaction is a thermometer needed

Answer 29

No

Question 30

Why is sodium carbonate used to wash the distillate produced from dehydration

Answer 30

The sodium carbonate would remove the H+

Question 31

Stages of fractional distillation

Answer 31

Turn the water on And begin the heat the solution with heating mantle This causes water and ethanol vapours to be evaporated Vapours pass up the fractioning colum Water is re condensed back into the solution Watch thermometer to keep temperature at the boiling point of ethanol Condenser C cools the ethanol vapours back into a liquid

Question 32

What do we do once we have distillates alcohol

Answer 32

Further separating to remove impurities using a separating funnel + drying agent

Question 33

How to make cyclohexene

Answer 33

1) distillation 2) separation - add water to dissolve soluble impurities, drain bottom layer 3) purification - add to round bottom flask add drying agent E,g, anhydrous calcium chloride then invert and leave for 30 mins

Question 34

Conditions for hydration

Answer 34

Steam + ethene + phosphoric acid catalyst Temp 300 Pressure 60 atm