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Chemistry OCR(A) A Level > M6 Chapter 26 - Carbonyls and Carboxylic Acids > Flashcards

M6 Chapter 26 - Carbonyls and Carboxylic Acids Flashcards

(58 cards)

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1
Q

What is the carbonyl group?

A

C=O

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2
Q

What is the functional group and general formula for an aldehyde?

A

RCHO

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3
Q

What is the functional group for a ketone?

A

RCOR’ (C=O)

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4
Q

How do you name aldehydes?

A

-al suffix (C=O is on the end of a chain)

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5
Q

How do you name ketones?

A

-one suffix (designate the number for which carbon C=O is on)

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6
Q

What kind of intermolecular forces do molecules with carbonyl groups have? Why?

A

Permanent dipole-dipole due to the C=O being polar.

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7
Q

How soluble are they in water? What influences solubility?

A

Yes they are soluble as they can form Hydrogen bonds and oxygen of of C=O. As chain length increases, solubility decreases.

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8
Q

Which bond in carbonyl compounds is usually involved in reactions?

A

C=O due to polarity of the bond (large difference in electronegativity)

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9
Q

What is the strongest bond in carbonyl compounds?

A

C=O

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10
Q

Draw a mechanism foe the nucleophillic addition of a carbonyl compounds using Nu:- to represent the nucleophile.

A

Arrow of Nu:- in to the C in the C=O.

Electron lone pair on O forms arrow with H+ (could be from water)

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11
Q

Draw a mechanism for the nucleophillic addition of HCN to a carbonyl compound.

A

CN:- arrows into C. Arrow from C=O to O forming dipoles.

Lone pair from O:- formed in previous step to H+

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12
Q

Why is the addition of HCN important?

A

Increases the length of the Carbon chain by one atom allowing for more useful molecules to be made.

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13
Q

Will the product of HCN added to a carbonyl compound have optical isomers? Why?

A

Yes. In the aldehyde/ketone, the carbonyl carbon is planar, so the :CN- can attack from either above or below forming two enantiomers.

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14
Q

What is the name of the product when HCN is added to a carbonyl compound?

A

Hydroxynitrile (OH and CN groups)

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15
Q

How do you test for a carbonyl compound?

A

Use 2,4 DNPH

If a carbonyl is present an orange precipitate is formed.

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16
Q

What is Tollens’ reagent?

A

Silver complex ions in colourless solution.

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17
Q

What happens when an aldehyde is added to Tollen’s reagent?

A

Silver Mirror forms as Ag+ is reduced to Ag (s)

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18
Q

What happens when a ketone is added to Tollen’s reagent?

A

No visible change

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19
Q

What is another oxidising agent for alcohols and aldehydes? What colour change does this undergo?

A

Acidified potassium dichromate (K2Cr2O7/H+). Colour change from orange to green.

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20
Q

What is a reducing agent for aldehydes and ketones? What ions does this release in solution?

A

NaBH4.
Releases H- ion.

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21
Q

Draw and name the mechanism for the reduction of an aldehyde.

A

Nucleophillic Addition (H:- going in, arrow on C=O going to O forming dipoles then next step is O:- formed has lone pair bonding to H+ in solution)

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22
Q

Write an equation for the reduction of pentan-2-one and for 3-methylbutanal.

A

CH3COCH2CH2CH3 + 2[H] –> CH3CH(OH)CH2CH2CH3

CH3CH2CH2(CH3)CHO + 2[H] –>

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23
Q

How do you convert an aldehyde to form a carboxylic acid?

A

Oxidation using Acidified Potassium Dichromate

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24
Q

Write out the mechanism for the nucleophillic substitution reaction of carbonyl compound with NABH4.

Study These Flashcards
A

H:- in. Arrow on C=O bond going to O to form dipoles.

Lone pair on same O has arrow to H+ to form OH.

25
What is the functional group of Carboxylic Acid?
-COOH
26
How do you name Carboxylic Acids?
-oic acid
27
Are carboxylic acids soluble in water? Why? What influences their solubility?
Yes because C=O is polar meaning can form Hydrogen bonds with water molecules.
28
What are the intermolecular forces in carboxylic acids?
Hydrogen Bonds in solid state - very strong.
29
What are esters (what are they formed from)? Functional group, general formula?
Formed from carboxylic acids and alcohols. RCOOR' (C=O and C-O-C)
30
Write an equation for the reaction of ethanoic acid with propan-1-ol.
CH3COOH + CH3CH2CH2OH --> CH3COOCH2CH2CH3 + H2O
31
How do you name esters?
Start with alcohol group that has replaced hydrogen, then acid part eg: propyl (from alcohol) ethanoate (from carboxylic acid)
32
What characteristic physical properties do esters have?
Volatile, pleasant fruity smells
33
What are some uses of esters?
Flavourings, perfumes (both for longer chains) Solvents (short chains)
34
How could you distinguish carboxylic acids from other -OH containing compounds?
Add NaHCO3. Acids will produce Sodium Salt, water and CO2.
35
Write an equation for the reaction of ethanoic acid and NaOH.
CH3COOH + NaOH --> CH3COO-Na+ + H2O
36
Write an equation for the reaction of ethanoic acid with Na2CO3.
2CH3COOH + Na2CO3 --> 2CH3COO-Na+ + H2O + CO2
37
Write an equation for the reaction of ethanoic acid with calcium oxide.
CH3COOH + CaO --> (CH3COO)2Ca + H2O
38
What catalyst is needed for the formation of esters from alcohols and carboxylic acids?
Concentrated strong acid (H2SO4)
39
What catalyst is needed for hydrolysis of esters?
Dilute strong acid eg: H2SO4.
40
What is an alternative method of hydrolysis?
Base Hydrolysis
41
What are the advantages of base hydrolysis?
Reaction goes to completion due to neutralisation by base - more product in the mixture than acid catalysed hydrolysis.
42
What are Carboxylic Acid derivatives?
Molecules with the acyl group as part of their structure, formed from carboxylic acids.
43
Name two acid derivatives and give their functional groups.
Acyl Chlorides = RCOCl Acid Anhydrides = RCOOCR (RCO)2O
44
How do you form an acyl chloride?
React carboxylic acids with SOCl2.
45
Draw the mechanism for the acylation of a nucleophile by an acid derivative.
:Nu- arrow in. C=O bond with arrow going to O forming neg dipole. Lone pair on same O:- goes back into C-O bond and C-X bond (usually H) has arrow going to H.
46
If the nucleophile is ammonia for the acylation of acyl chlorides or acid anhydrides, what are the products of the reaction?
An amide.
47
Write an equation for the reaction of ethanoyl chloride and ammonia.
CH3COCl + NH3 --> CH3CONH2 + NH4Cl
48
Draw the mechanism for the reaction of ethanoyl chloride and ammonia.
N:H3 arrow to C in C=O. Arrow going to in C=O from bond forming O dipole. Arrow of lone pair going back into C=O, arrow of C-Cl going to Cl and H on the ammonia going to the N+ to form an NH2 that attaches.
49
If the nucleophile is a primary amine, what are the products of the acylation of acyl chlories or acid anhydrides?
N-substituted amide.
50
Write an equation for the reaction of ethanoyl chloride and methylamine.
CH3COCl + CH3NH2 --> CH3CONHCH3 + CH3NH3Cl
51
Draw the mechanism for the reaction of ethanoyl chloride and methylamine.
Refer to previous slides or goodnotes.
52
If the nucleophile is an alcohol, what are the products of the acylation of acyl chlorides or acid anhydrides?
An ester.
53
Write an equation for the reaction of ethanoyl chlorides and ethanol.
CH3COCl + CH3CH2OH --> CH3COOCH2CH3 + HCl
54
Draw the mechanism for the reaction of ethanoyl chloridea and ethanol.
Refer to memory lil bro.
55
If the nucleophile is water, what are the products of the acylation of acyl chlorides or acid anhydrides?
Carboxylic Acid
56
What is the name of this reaction (the acylation of acyl chlorides/acid anhydrides with water as a nucleophile)?
Hydrolysis
57
Write an equation for the reaction of ethanoyl chloride and water.
CH3COCl + H2O --> CH3COOH + HCl
58
Draw the mechanism for the reaction of ethanoyl chloride and water.
Refer elsewhere lil bro. Mans cant draw it here.

Chemistry OCR(A) A Level (14 decks)

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