3.3.5 Alcohols

Question 1

How alcohols classified

Answer 1

How many carbon atoms bonded to the carbon the oh bonded to
2 = secondary
3 = tirsuary

Question 2

Bonding alcohols has

Answer 2

Hydrogen bonding as o nad h

Question 3

Test to tell the difference between the types of alcohols

Answer 3

Primary alcohols - oxidised-aldehydes
Secondary alcohols - oxidised - ketones
Oxidising agent potassium dichromate
Tertiary alcohols do not undergo oxidation
Orange → green

Question 4

Oxidation of alkenes formula

Answer 4

alkene + oxidising agent = alkane
o in square brackets

Question 5

Oxidation of alcohols digram

Answer 5

1st - aldehydes - carboxylic acid

2nd - keton

Question 6

Method for oxidising the alcohols

Answer 6

Primary alcohol is added to the oxidising agent and warmed
The aldehyde product has a lower boiling point so is distilled of before it turns into a carboxylic acid in excess oxidising agents
(ketones don’t need to b e distilled of

Question 7

hydration/electrophilic addition to make an alcohol

Answer 7

Conditions - alkene and steam - heta with h2p04 catalyst

Question 8

Nucleophilic substitution for production of alcohols

Answer 8

Conditions - halogenoalkane - acquiesce sodium hydroxide - heat

Question 9

Reduction to make alcohols not carboxylic acids

Answer 9

aldehydes/ ketones - nabh4 / lialh4

Question 10

Reduction to make alcohols from carboxylic acids

Answer 10

Reduction to make alcohols from carboxylic acids

Question 11

What is the oxidising agents to make alcohols

Answer 11

Acidified potassium dichromate k2cr207
Or acidified [potassium manganate kmno4 (purple to colourless when oxidised )

Question 12

How to test for oxidation products

Answer 12

Fehling’s solution
Alkaline copper 2+ions
Aldehyde to carboxylic acids cu2+ is reduced to cu
Ketone = neg result
Pos = clear blue to opaque red ppt

Tollens reagent
Alkaline solution silver nitrate in excess ammonia
Warmed with aldehyde - carboxylic acids
Ag+ to ag
Ketones result is negative as doest oxidise further

Clear → silver mirror

Question 13

Elimination reaction mechanism

Answer 13

alchol vapour passed over hot catalyst Al2O3
or sulfuric acid or phosphoric acid

the lone pair on the alchol group electrons move to the the h+ from the catalyst - arrow

arrow breaking the bond between the now water and teh carbon
creats a carbo cation

the h on the other carbon next to c-h bond collapeses into c-c

creats a double bond

Question 14

Elimination from alcohols to alkenes conditions

Answer 14

Thai si dehydration
Alcohol vapour is passed over a hot catalyst (al2o3) or sulfuric acid or phosphoric acid

Question 15

Ways of making ethanol

Answer 15

Fermentation of glucose
Hydration of ethene

Question 16

Fermentation of glucose points

Answer 16

C6h12o6 → 2ch3ch2oh +co2
Yeast
Anaerobic respiration
Low temperature
Renewable
Cheap
Made in batches
Ethanol needs distilling

Question 17

Elimination of ethene points

Answer 17

C2h4 + h2o reversible → ch3ch2oh
High temp 300 degrees
High pressure
6oatm
Catalyst of conc h2so4
Continuous
Non renewable
Pure product that doesn’t need to be distilled

Question 18

Ketone and aldehyde shape

Answer 18

Ketone = middle 0
Aldehyde = end 0h
Double bond for both

Question 19

Ethanol as a biofuel equations and limitations

Answer 19

Limitations - doest take into account the transport and machinery

Photosynthesis : 6co2 +6h20 → c6h12o6
Ferment: c6h12o6 _> 2c2h5oh + 2c02
Combust: 2c2h5oh + 6o2 → 4co2 + 6h2o

Question 20

Electrophilication

Answer 20

carbocations , form depending on what is more stable