alcohols part 2 Flashcards

1
Q

what three important reactions do alcohols take part in

A
  • combustion
  • elimination
  • oxidation
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2
Q

what do alcohols burn in oxygen to form

A

co2 and water

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3
Q

why do alcohols combust more efficiently than alkanes

A

presence of O atom

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4
Q

what does an alcohol react to form in an elimination reaction

A

an alkene

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5
Q

elimination

A

a reaction in which an atom/group of atoms is removed from a reactant

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6
Q

why do elimination reactions of alcohol involve dehydration

A

water is eliminated

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7
Q

reagent elimination

A

conc h2so4

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8
Q

conditions elimination

A

heat

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9
Q

elimination of alchools what happens

A
  • oh group always removed
  • h atom from an adjacent c also removed
  • double bond forms between 2 c atoms
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10
Q

what can alcohols be oxidised by

A

oxidising agents such as acidifed potassium dichromate

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11
Q

what happens to acidified potassium dichromate when it acts as an oxidising agent

A

changes orange to green

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12
Q

half equation oxidation of alcohols

A

Cr2O72- + 14H+ + 6e- > 2Cr3+ + 7h2o

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13
Q

what is a primary alcohol oxidised to

A

an aldehyde and then to a carboxylic acid

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14
Q

general equation oxidation of primary alcohol

A

RCH2OH + {O} > RCOH + H2O

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15
Q

reagent and conditions oxidation primary

A

acidified potassium dichromate/ H+

gentle heat and distil

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16
Q

observation oxidation primary

A

orange to green

17
Q

why is the product of oxidation of primary alcohol likely to be an aldehyde

A

aldehyde will have lower boiling point than alcohol it was formed from
reaction hasn’t been given chance to go any further

18
Q

oxidation of ethanol symbol equation

A

CH3CH2OH + [O] > CH3CHO + H2O

19
Q

oxidation to carboxylic acid general equation

A

RCH2OH + 2[O] > RCOOH + H2O

20
Q

why is it 2[O] in symbol equation oxidation to carboxylic acid

A

alcohol being oxidised further

21
Q

conditions oxidation to carboxylic acid

A

cr2o72-/H+ heat and reflux

22
Q

why is product likely to be carboxylic acid

A
  • reaction given chance to go to completion

- no products able to condense and separate

23
Q

how can the carboxylic acid be removed from the reaction mixture when the reaction is complete

A

distillation

24
Q

oxidation of ethanol to carboxylic acid symbol equation

A

CH3CH2OH + 2[O] > CH3COOH H2O

25
Q

what is a secondary alcohol oxidised to

A

a ketone

26
Q

can ketones be oxidised

A

no

27
Q

general equation oxidation secondary alcohols

A

RCOHR1 + [O] > RCOR1 + H2O

28
Q

reagents and conditions oxidation secondary alcohol

A

acidified potassium dichromate

heat and relflux

29
Q

symbol equation oxidation of propan-2-ol (seoncdary)

A

CH3CHOHCH3 + [O] > CH3COCH3 + H2O

30
Q

Apparatus for oxidation to a carboxylic acid

A

Reflux

31
Q

Apparatus oxidation of primary alcohols

A

Immediate distillation

32
Q

How can the presence of an aldehyde functional group be confirmed

A

Using mild oxidising agents such as tollens or fehlings

33
Q

Observations tollens reagent

A

Silver mirror seen

34
Q

Organic product silver mirror test

A

Carboxylic acid

35
Q

Observations fehlings solution

A

Blue solution to brick red pot

36
Q

How can the presence of a carboxylic acid functional group be confirmed

A

Using sodium carbonate

37
Q

Observations carboxylic acid and sodium carbonate

A

Effervescence

38
Q

Organic product sodium carbonate and carboxylic acid

A

Carboxylate salt

RCOO-Na+

39
Q

General equation carboxylic acid and sodium carbonate

A

2RCOOH+ Na2CO3 > 2RCOONa + CO2 + H2O