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AL. OCR Chemistry > carbonyls and carboxylic acids > Flashcards

carbonyls and carboxylic acids Flashcards

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1
Q

why are aldehydes easy to oxidise?

A

as H atom is attached to the carbonyl group

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2
Q

what happens to solubility of carboxylic acids as chain length increases?

A

decreases - as hydrocarbon tails ‘get in the way’, breaking h bonds between carbon and water, reducing solubility

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3
Q

tollen’s test

A

Ag+ ins oxidise aldehyde, reducing Ag+ to Ag

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4
Q

other name for Brady’s solution

A

2,4 - dinitrophenylhydrazine

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5
Q

what is Brady’s test for

A

aldehyde and ketone

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6
Q

positive Brady’s result

A

orange ppt.

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7
Q

esterification

- conditions

A

reaction of alcohol with carboxylic acid to form and ester - in presence of H2SO4 (conc)

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8
Q

hydrolysis of ester - product and conditions

A
  • hot aqueous acid –> parent carb. acid

- hot aqueous alkali –> carboxylate ion

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9
Q

acid hydrolysis

A
  • reverse reaction of esterfication
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10
Q

acid hydrolysis - conditions - - explain products

A
  • ester refluxed with dilute aqueous acid
  • broken down by water with acid acting as catalyst
  • carb. acid and alcohol
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11
Q

alkaline hydrolysis

A

ester refluxed with aqueous alkali

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12
Q

products of alkaline hydrolysis

A

carboxylate ion and alcohol

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13
Q

acyl chloride + alcohol =

A

HCl and ester

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14
Q

acyl chloride + phenol =

A

HCl and ester

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15
Q

acyl chloride + water =

A

HCl and carboxylic acid

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16
Q

acyl chloride + ammonia =

A

ammonium chloride and primary Amide

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17
Q

carbonyl functional group

A

C=O

18
Q

carboxylic acid + … –> acyl chloride

A

SOCl2

19
Q

acyl chloride + amine =

A

secondary amide

20
Q

ester functional group

A

COO

21
Q

advantages of using acid anhydrides instead of carboxylic acids to make esters

A
  • position of equilibrium is further right so yield is higher
  • no conc. acid catalyst required
22
Q

disadvantages of using acid anhydrides instead of carboxylic acids to make esters

A
  • lower atom economy
23
Q

differences between acid and alkaline hydrolysis of esters

A

alkane hydrolysis produces carboxylate salt instead of carb acid

24
Q

naming esters

A

alcohol gives first part of name

carboxylic acid gives second part

25
Q

acyl chlorides formed form..

A

carboxylic acid and sulfonyl chloride

26
Q

how to form alcohol from aldehyde

- what type of alcohol formed?

A

warm w. aq. NaBH4

- primary

27
Q

how to form alcohol from ketone

- what type of alcohol formed?

A

warm w. aq. NaBH4

- secondary

28
Q

what chemicals are used in the lab provide HCN in a reaction?

A

NaCN and H2SO4

29
Q

what is useful about reaction between carbonyls and HCN

A

increases carbon chain length

30
Q

how to identify aldehyde or ketone by 2,4-DNP (Bradys)

A
  • filter solution to collect yellow/range ppt.
  • solid then recrystallised to produce pure sample of crystals
  • melting point is measured and recorded
  • compare melting point to database to identify carbon compound
31
Q

maximum number of carbon atoms in a carboxylic acid which is soluble in water

A

4

32
Q

2 types of acid reactions of carboxylic acids

A
  • redox with metals

- neutralisation with bases (eg. metal oxides, carbonates, alkalis)

33
Q

carb. acid + metal ->

A

H2 + Carboxylate salt

34
Q

carb. acid + metal oxide ->

A

salt + water

35
Q

carb. acid + alkali ->

A

salt + water

36
Q

carb. acid + carbonates ->

A

salt + water + carbon dioxide

37
Q

carb acid derivative?

A

compound which can he hydrolysed to form parent carb. acid

38
Q

common group of atoms all carb. acid derivatives share

A

acyl group
R - C = O
|

39
Q

carb acid derivatives (4)

A
  • esters
  • acyl chlorides
  • acid anhydrides
  • amides
40
Q

product of alkaline hydrolysis with NaOH

A

sodium ethanoate salt

41
Q

method for esterification (from acid and alcohol)

A
  • 2cm3 ethanol + 2cm3 propanoic acid -> boiling tube
  • add drops conc. H2SO4
  • hot water bath at 80C - 5 mins
  • pour into beaker w. Na2CO3 (aq)
    [oily ester will float on surface]
42
Q

why does radical substitution result in mixture of products

A
  • further substitution can occur

- substitution at different places along the chain

AL. OCR Chemistry (20 decks)

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