Unit 4.5 - Carboxylic acids and their derivatives Flashcards
1
Q
General formula of carboxylic acids + explain
A
RCOOH
R is a hydrogen, alkyl group or aromatic group
2
Q
What functional group do carboxylic acids?
A
The carboxylic one
3
Q
How are carboxylic acids named?
A
By adding the suffix -oic acid to the alkane stem
4
Q
Compare the infrared spectrums of alcohols and carboxylic acids
A
Alcohol = broad OH peak
Carboxylic acid = peak is broader with an additional sharp peak due to the carbonyl group
5
Q
Another word for ethanoic acid
A
Formic acid
6
Q
Another word for acetic acid
A
Ethanoic acid
7
Q
Another word for benzene carboxylic acid
A
Benzoic acid
8
Q
Formic acid
A
methanoic acid
9
Q
Acetic acid
A
Ethanoic acid
10
Q
benzoic acid
A
Benzene carboxylic acid
11
Q
Benzoic acid shortened structural formula
A
C6H5COOH
12
Q
What happens in the derivatives of carboxylic acids?
A
The -OH group is replaced by other functional groups
13
Q
Derivative if the OH group in a carboxylic acid is replaced with Cl
A
Acid chloride
14
Q
Derivative if the OH group in a carboxylic acid is replaced with OR’
A
Ester
15
Q
How do you get an ester?
A
React an alcohol with a carboxylic acid
16
Q
Derivative if the OH group in a carboxylic acid is replaced with -OCOR’
A
Acid anhydride
17
Q
What’s the only acid anhydride that we deal with?
A
Ethanoic anhydride
18
Q
Derivative if the OH group in a carboxylic acid is replaced with NH2
A
Amide
19
Q
Amide functional group
A
-NH2
20
Q
Acid anhydride functional group
A
-OCOR’
21
Q
Derivative if the OH group in a carboxylic acid is replaced with C———N
A
Nitrile
22
Q
Nitrile functional group
A
C=—N (triple bond)
23
Q
Why is it strange that nitriles are classed as carboxylic acid derivatives?
A
Since the nitrile functional group hasn’t replaced any OH’s
24
Q
Ethyl ethanoate shortened structural formula
A
CH3COOCH2CH3
25
CH3COOCH2CH3
Ethyl ethanoate
26
Methyl butanoate
CH3CH2CH2COOCH3
27
CH3CH2CH2COOCH3
Methyl butanoate
28
Ethanoyl chloride
CH3COCl
29
CH3COCl
Ethanoyl chloride
30
Propanoyl chloride
CH3CH2COCl
31
CH3CH2COCl
Propanoyl chloride
32
Ethanamide
CH3CONH2
33
CH3CONH2
Ethanamide
34
But an aide
CH3CH2CH2CONH2
35
CH3CH2CH2CONH2
Butanamide
36
Propanenitrile
CH3CH2CN
37
CH3CH2CN
Propanenitrile
38
Ethanoic anhydride
(CH3CO)2O
39
(CH3CO)2O
Ethanoic anhydride
40
Aspirin
Ethanoic anhydride
41
Methyl benzene carboxylate
C6H5COOCH3
42
C6H5COOCH3
Methyl benzene carboxylate
43
Sodium butanoate
CH3CH2CH2CH2COONa
44
CH3CH2CH2COONa
Sodium butanoate
45
2-hydroxyethanoic acid
CH2OHCOOH
46
CH2OHCOOH
2-hydroxyethanoic acid
47
Where is “1” whenever deciding on the position of a different functional side group on a carboxylic acid?
Wherever the carboxylic acid carbon is
48
What is it if OH- is directly bonded to a benzene?
Phenol, not an alcohol
49
What have the same molecular structures?
Esters and carboxylic acids
50
What can we do since esters and carboxylic acids have the same molecular structures?
Can work out their structural isomers
51
What’s the same between esters and carboxylic acids?
Same molecular structures
52
How do we work out the possibly isomers of an ester?
Write it out, work out the molecular formula and remember that the isomers can be esters and carboxylic acids
53
Methods of preparing carboxylic acids
Oxidation of primary alcohols
Hydrolysis of nitriles
Hydrolysis of amides
Preparation of aromatic carboxylic acids
54
How are carboxylic acids prepared from the oxidation of primary alcohols?
The alcohol is refluxed with acidified potassium dichromate (VI)
55
Explain the two routes in which a carboxylic acid can be formed from primary alcohols
Mildly oxidised with acidified potassium dichromate (VI) to give an aldehyde and then reflux with more acidified potassium dichromate (VI) to give a carboxylic acid
Or, just reflux initially with acidified potassium dichromate (VI) to give a carboxylic acid
56
What happens during he hydrolysis of nitriles
The nitrile is refluxed with dilute HCl/aqueous NaOH
57
Give the equation for the hydrolysis of Propanenitrile with dilute HCl
CH3Ch2CN ——> CH3CH2COOH + NH4Cl
58
What is the better route to use when undergoing the hydrolysis of nitriles?
To use aqueous sodium hydroxide
59
Why is it a better route to use aqueous sodium hydroxide for the hydrolysis of nitriles?
Since a salt of the acid is formed
60
Describe the reaction of the hydrolysis of nitriles using aqueous NaOH
With sodium hydroxide, the sodium salt is formed. A strong acid (HCl) is added in order to form the acid. The HCl releases the acid from the salt to become a free acid.
61
What does adding HCl to the sodium salt during the hydrolysis of nitriles do?
It releases the acid from the salt to become a free acid
62
Free acids
Released from the salt
63
Name for acids released from a salt
Free acids
64
Equation for the hydrolysis of Propanenitrile using aqueous sodium hydroxide
CH3Ch2CN —> (adding NaOH) CH3Ch2COONa + NH3 —> (adding HCl) CH3CH2COOH
65
Describe the hydrolysis of amides to prepare carboxylic acids
The amide is refluxed with dilute HCl/aqueous sodium hydroxide and the course of the reactions is similar to that with nitriles
66
Give the equation for the hydrolysis of Ethanamide with aqueous sodium hydroxide
CH3CONH2 —> (adding NaOH) CH3COONa + NH3 —> (adding HCl) CH3CH2COOH
67
Equation for the hydrolysis of Ethanamide with HCl
CH3CONH2 —> CH3COOH + NH4Cl
68
How are aromatic compounds formed differently to aliphatic ones?
They have a different oxidising agent
69
What is benzene *not* oxidised by and why?
Potassium manganate (VII) since it’s aromatic with no methyl side group
70
When can oxidation of benzene occur?
When there’s a methyl side group on the benzene ring
71
How is an aromatic carboxylic acid formed from methyl benzene?
When refluxed with an alkaline (in sodium carbonate) potassium manganate (VII) and the mixture subsequently acidified, an aromatic carboxylic acid is formed
72
Type of potassium manganate (VII) needed to acidify methyl benzene
Alkaline (in sodium carbonate)
73
Alkaline potassium manganate (VII)
In sodium carbonate
74
What is formed when methyl benzene is refluxed with alkaline (in sodium carbonate) potassium manganate (VII) and the mixture subsequently acidified?
Benzene carboxylic acid
75
How is the free acid formed during the acidification of methyl benzene?
By adding HCl
76
What type of alkaline needs to be used to make potassium manganate (VII) alkaline for the preparation of benzene carboxylic acid?
Hot sodium carbonate
77
What type of benzene do we oxidise to form an aromatic carboxylic acid?
An alkyl benzene
78
Describe the boiling points of carboxylic acids
The lower homologues are liquids with boiling points considerably higher than that of alkanes of similar molar mass
79
What type of bonds can carboxylic acids form with each other?
Hydrogen
80
How come carboxylic acids can form hydrogen bonds with each other?
Due to the presence of the OH group
81
Why do carboxylic acids have boiling points considerably higher than that of alkanes of similar molar mass?
Because they form hydrogen bonds between each other, which require more energy to break that just the Van der Waal forces in alkanes
82
What type of carboxylic acids have higher boiling points than alkanes of similar molar mass?
The lower homologues
83
What are the lower homologues of carboxylic acids soluble in?
Polar solvents such as water and non-polar solvents such as benzene
84
What type of carboxylic acids are soluble in polar solvents such as water but also non-polar solvents such as benzene?
Lower homologues
85
Why are lower homologues of carboxylic acids soluble in polar solvents such as water?
Due to the presence of C=O and OH groups - forms hydrogen bonds
86
What type of solvent is benzene?
Non-polar
87
Name a non-polr solvent
Benzene
88
Why are lower homologues of carboxylic acids soluble in non-polar solvents such as benzene?
Due to the presence of the hydrocarbon chin
89
What happens to the solubility of the carboxylic acid as the chain length increases?
Decreases
90
What property of a carboxylic acid can affect its solubility?
Chain length
91
Why does the solubility of carboxylic acids decrease as the chain length increases?
The contribution of hydrogen bonding becomes less effective as the size of the hydrocarbon chain increases- there are more non-polar groups which outweigh the polar groups
92
Chemical reactions of carboxylic acids to remember
Acidity
Reduction - (lithium aluminium hydride)
Decarboxylation
Esterification
Formation of acid chlorides
93
What type of acids are carboxylic acids?
Weak ones
94
Weak acid
Only partially dissociated into its ions in solution
95
How do we know that carboxylic acids are weak acids in aqueous solution?
About 1-2% of the molecules are dissociated into their ions
96
Carboxylic acids dissociating into their ions in aqueous solution
CH3COOH + H2O —><— CH3COO- + H3O+
97
What do carboxylic acids do with blue litmus? Why?
Turn it red
pH < 7
98
How do we know that carboxylic acids are weak acids
Turn blue litmus red, pH<7
Release carbon dioxide gas with carbonates and hydrogen carbonates
99
What happens when carboxylic acids react with carbonates and hydrogencarbonates?
They release CO2 gas
100
Equation for the reaction between sodium carbonate and ethanoic acid
Na2CO3 + 2CH3COOH —> 2CH3COONa + CO2 + H2O
101
What are the only things that react with carbonates and hydrogen carbonates to give a salt, CO2 and H2O?
Carboxylic acids
102
Which reaction is used as a test for carboxylic acids?
React with carbonates and hydrogen carbonates
103
Observation for a positive test for a carboxylic acid with a carbonate or hydrogencarbonate
Effervescence
Lime water turns milky
104
Lime water
Calcium hydroxide
105
Calcium hydroxide
Limewater
106
Describe the salts of carboxylic acids
Ionic substances
High melting points
Tend to be soluble in water
107
List the following in terms of acidic strength:
Phenol, water, ethanoic acid, methanol
(Weakest first)
Methanol
Water
Phenol
Ethanoic acid
108
Ka from pKa
Ka = 10^-pKa
109
pKa from Ka
pKa = -log10(Ka)
110
How do we identify the strength of an acid in terms of pKa?
Lower pKa = stronger
111
How do we identify the strength of an acid in terms of Ka?
Higher Ka = stronger
112
What is the acidity of the compounds methanol, water,phenol and ethanoic acid largely dependent on?
The stability of the anion
113
How is an anion stabilised?
By the delocalisation of the negative charge on the anion
114
Explain how the acidity of compounds depends on the stability of the anion?
An anion is stabilised by delocalisation of the negative charge on the anion. Thus, the greater the delocalisation of the negative charge, the most stable will be the anion and the greater will be the acidic strength of the compound.
115
What does greater delocalisation of the negative charge on an anion lead to?
A more stable anion and the greater the acidic strength of the compound
116
What does a more stable anion lead to?
Greater acidic strength of the compound
117
How does a compound have greater acidic strength?
By having a More stable anion
118
How is an anion more stable?
With greater delocalisation of the negative charge
119
Explain why methanol and water are very weak acids
There is no delocalisation
There is no anion
120
Why is methanol a weaker acid than water?
The methyl group decreases the effect of the negative charge on the oxygen, making it a weaker acid than the water.
121
Explain why phenol is a stronger acid than water
The negative charge on the anion is partially delocalised into the ring which stabilises the negative charge
122
Explain why ethanoic acid is a stronger acid than phenol
In ethanoic acid, the negative charge is delocalised to a considerable extent in the ethanoate ion. This makes ethanoic acid a stronger acid than phenol as the extent of anion stabilisation due to delocalisation is greater.
123
How are anions stabilised?
By delocalisation
124
what does delocalisation do to anions?
Stabilises them
125
What will the anion from phenol react with and what won’t it react with?
Will react with sodium hydroxide
Not with sodium carbonate
126
What will the anion from phenol do with neutral iron (III) chloride?
Will give a violet colourisation
127
What will an anion from a carboxylic acid react with?
Sodium hydroxide and sodium carbonate solution
128
What will an anion from a carboxylic acid do with neutral iron (III) chloride?
Will *not* give a violet colourisation
129
What do phenols give a violet colourisation in?
Neutral iron (III) chloride
130
Are carboxylic acids readily reduced? How do you know?
No
They’re not reduced by NaBH4
131
How are carboxylic acids reduced?
With lithium aluminium hydride
132
What are carboxylic acids reduced to with lithium aluminium hydride?
Primary alcohols
133
Conditions for carboxylic acids being reduced with lithium aluminium hydride to primary alcohols
The acid is reacted with LiAlH4 dissolved in ether at room temperature
The reaction must be carried out under dry conditions as LiAlH4 reacts violently with water
134
Why must the reduction of carboxylic acids be done under dry conditions?
As LiAlH4 reacts violently with water
135
Equation for the reduction of ethanoic acid
CH3COOH + 4[H] (from LiAlH4) ——> CH3CH2OH
136
What happens during a decarboxylation reaction?
The carboxylic acid loses the elements of CO2
137
What is formed after the decarboxylation of a carboxylic acid?
An alkane or an aromatic hydrocarbon
138
Describe the alkane formed after the decarboxylation of a carboxylic acid
Has one less carbon than the carboxylic acid
139
How is the carboxylic acid treated for its decarboxylation to occur?
The carboxylic acid or more conveniently, its sodium salt, is heated with soda-lime [Ca(OH)2/NaOH]
140
Soda-lime + what reaction of carboxylic acids is it used for?
[Ca(OH)2/NaOH]
Decarboxylation
141
Decarboxylation of CH3COOH equation
CH3COOH ————> CH4
[Ca(OH)2/NaOH]
142
Decarboxylation of CH3CH2COOH equation
CH3CH2COOH ———> CH3CH3
[Ca(OH)2/NaOH]
143
What is decarboxylation usually carried out using and why?
Using the sodium salt of the acid rather than the acid itself as it’s generally more effective
144
What can we use to represent the equinox for decarboxylation using soda lime?
Using calcium hydroxide, calcium oxide or sodium hydroxide
145
Conditions for the esterification of a carboxylic acid
Heated in the presence of concentrated sulfuri acid
Refluxed
146
Describe and explain the process of esterification in the absence of sulfuric acid
Very slow
Concentrated sulfuric acid is a dehydrating agent, removing water from the equilibrium mixture. The position of equilibrium goes to the right and the reaction goes to completion.
147
Equation for the esterification of CH3COOH
CH3COOH + CH3CH2OH —><— CH3COOCH2CH3 + H2O
148
What are the reagents that can be used to make acid chlorides?
Phosphorus trichloride PCl3
Phosphorus pentachloride PCl5
Sulphur dichloride oxide SOCl2
149
What can the following reagents be used for?
Phosphorus trichloride PCl3
Phosphorus pentachloride PCl5
Sulphur dichloride oxide SOCl2
Making acid chlorides
150
Explain the process of making acid chlorides with PCl5 as the reagent
The reaction takes place by reacting a carboxylic acid with phosphorus (v) chloride at room temperature under anhydrous conditions - as both phosphorus (v) chloride and the product ethanoyl chloride react violently with water
Since HCl gas is released in the reaction, the preparation must be carried out in a fume cupboard
151
Why must the reaction of the formation of acid chlorides with PCl5 be carried out under anhydrous conditions and in a fume cupboard?
Anhydrous conditions —> both PCl5 and the product ethanoyl chloride react violently with water
Fume cupboard —> as HCl gas is released in the reaction
152
Equation for the reaction between ethanoic acid and PCl5
CH3COOH + PCl5 ——> CH3COCl + POCl3 + HCl
153
Equation for the reaction between ethanoic acid and PCl3
3CH3COOH + PCl3 —> 3CH3COCl + H3PO3
154
What is the preferred reagent to be used for the production of acid chlorides?
SOCl2
155
Gaseous coproducts when forming acid chlorides with SOCl2
SO2 and HCl
156
Equation for the reaction between ethanoic acid and SOCl2
CH3COOH + SOCl2 —> CH3COCl + SO2 + HCl
157
Stages for the formation of amides from carboxylic acids
1. The carboxylic acid is initially reacted with dilute aqueous ammonia. In this reaction the salt ammonium ethanoate is formed.
2. When the mixture is heated, the salt loses water and an amide is formed.
158
Equations for the formation of an amide from CH3COOH
CH3COOH + NH3 —> CH3COONH4
CH3COONH4 —> CH3CONH2 + H2O
159
Better method for the formation of amides from carboxylic acids than the 2 step reaction with dilute aqueous ammonia and heating
Heat the acid or the ammonium salt with urea at 120 degrees
160
Products when reacting a carboxylic acid and urea
Amide
CO2
NH3
161
2 ways of forming nitriles
1. From amides
2. From halogenoalkanes
162
How do you get nitriles from amides?
Amides can be dehydrated by heating with phosphorus (v) oxide P4O10 to give the corresponding nitrile
163
How do you form nitriles from halogenoalkanes?
The reaction is carried out by refluxing a solution of potassium cyanide in ethanol
164
Explain the produce when nitriles are formed from halogenoalkanes
There is an extra carbon atom in the product and the reaction can be used to ascent the homologous series - increase the length of the carbon chain
165
Equation for the reaction between 1-bromopropane and KCN (in ethanol)
CH3CH2CH2Br + KCN —> CH3CH2CH2CN + KBr
166
Reagent, conditions and product for the formation of nitriles form halogenoalkanes `
Reagent = potassium cyanide
Conditions = ethanol (solvent), reflux
Product = nitrile
167
What’s the product of alkaline hydrolysis when the derivatives of carboxylic acids are hydrolysed?
The carboxylic acid
168
What’s the product of acid hydrolysis when the derivatives of carboxylic acids are hydrolysed?
The carboxylic acid
169
Explain the hydrolysis of acid chlorides to give carboxylic acids
Acid chlorides are hydrolysed readily by water at room temperature
The reaction may be violent and misty white fumes of HCl gas are released
170
Equation for the hydrolysis of propanoyl chloride
CH3CH2CH2COCl + H2O —> CH3CH2COOH + HCl
171
Explain the options for the hydrolysis of amides and nitriles
They have to be heated with alkalis or acids
The reaction with alkalis occurs more readily but the *salt* of the carboxylic acid is formed and acid must be added to obtain the free acid
172
Which hydrolysis reaction of amides and nitriles occurs more readily but what is the issue with it?
The reaction with alkalis occurs more readily but the *salt* of the carboxylic acid is formed and acid must be added to obtain the free acid
173
What are used as reagents for the hydrolysis of amides and nitriles and why?
Sodium hydroxide or hydrochloride acid
The reaction is very slow with water
174
Explain the base catalysed reaction for the hydrolysis of modes and nitriles
The salt is formed with amides and nitriles. The mixture is refluxed. Ammonia gas, which turns red litmus blue, is given off with both reagents. HCl is added to generate the free acid.
175
How can we identify ammonia gas?
Turns red litmus blue
176
Equation for the hydrolysis of ethanamide or ethane nitrile to a carboxylic acid
CH3CONH2 or CH3CN ——> CH3COONa + NH3 ——> CH3COOH
NaOH. HCl
177
Explain the acid catalysed reaction for the hydrolysis of amides and nitriles to carboxylic acids
Acid is formed with amides and nitriles. The mixture is refluxed.
178
Equation for the acid catalysed hydrolysis of ethanamide or ethaneitrile
CH3CONH2 or CH3CN ——> CH3COOH + NH4Cl
HCl
179
How are esters hydrolysed by water?
Very slowly
180
Conditions for the hydrolysis of esters
Base catalysed or acid catalysed
The reagents are refluxed
181
General equation for the hydrolysis of esters
ester + water —><— carboxylic acid + alcohol
182
Equation for the hydrolysis of ethyl ethanoate
CH3COOCH2CH3 + H2O —><— CH3COOH + CH3CH2OH
183
Which reaction is the reverse of esterification?
The hydrolysis of esters
184
What is the product of the hydrolysis of esters when the reaction is base catalysed using aqueous sodium hydroxide solution?
The salt of the carboxylic acid - CH3COONa
185
Explain base catalysed hydrolysis of ester reactions
The alkali forces the position of equilibrium to move to the right by removing the acid, which if formed by reaction with it to form the salt
186
Are the hydrolysis of esters reactions normally base or acid catalysed? Why?
Base catalysed
The alkali forces the position of equilibrium to move to the right by removing the acid, which is formed by reacting with it to form the salt
In this way, the reaction can go to completion and this is why the reaction is normally based on catalysed
187
Which reaction is more efficient for the hydrolysis of esters - base or acid catalysed?
Base catalysed
188
Which cause more damage when spilt on clothes made from polyesters - acids or alkalis? Why?
Allkalis
In the hydrolysis of esters, alkali forces the position of equilibrium to move to the right by removing the acid, which is formed by reacting with it to form the salt
189
What is used during the reduction of nitriles?
Lithium tetrahydridoaluminate (III) - LIAlH4
190
What are nitriles reduced to?
Primary amines
191
What do primary amines form from the reduction of?
Nitriles
192
Conditions for the reduction of nitriles
The reagents are refluxed in ether (ethoxyethane) under anhydrous conditions
193
Equation for the reduction of ethanenitrile
CH3CH + 4[H] —> CH3CH2NH2
194
CH3Ch2NH2
Aminoethane/ethylamine
195
Possible reagents for the reduction of nitriles
LiAlH4
Hydrogen and nickel catalyst
Sodium metal/ethanol
196
Preferred reagent for the reduction of nitriles + why
LiAlH4
Yields are higher
197
What happens when you reduce nitriles with sodium/ethanol as a reagent?
It produced a secondary amine as a byproduct
198
Equation for the reduction of ethanenitrile with sodium/ethanol as a reagent
CH3CH2CN —> CH3Ch2Ch2NH2 + (CH3CH2CH2)2NH
199
Explain the positive character of the carbon in ethanoyl chloride
The presence of two highly electronegative atoms, oxygen and chlorine, bonded to a carbon atom increases the positive character of the carbon considerably
200
Which element has a positive character in ethanoyl chloride?
Carbon
201
What does ethanoyl chloride react readily with?
Water
Alcohols
Phenol
Primary amines
Ammonia
202
What reacts readily with all of the following?
Water
Alcohols
Phenol
Primary amines
Ammonia
Ethanoyl chloride
203
What does ethanoyl chloride form with water?
Carboxylic acid
204
What does ethanoyl chloride form with alcohols?
Ester
205
What does ethanoyl chloride form with phenol?
Ester
206
What does ethanoyl chloride form with primary amines?
N-substituted amide
207
what does ethanoyl chloride form with ammonia?
Amide
208
What happens in all of the reactions of ethanol chloride?
HCl is eliminated from the product
209
Conditions for all of the reactions of ethanoyl chloride
Room temperature
Anhydrous conditions
210
Equation for the reaction of ethanoyl chloride and propanoic acid
CH3COCl + CH3Ch2CH2OH —> CH3COOCH2CH2CH3 + HCl
211
What is terylene?
Polyester
212
other name for polyester?
Terylene
213
What type of reaction is terylene made in?
A condensation reaction
214
Explain the condensation reaction of terylene
Condensation reaction i.e - by the reaction of two bifunctional molecules to form the polymer with the elimination of water
215
What is terylene mainly used as?
A synthetic fibre
216
What are the 2 compounds which are reacted to form terylene?
Benzene- 1,4 - dicarboyxlic acid (terephthalic acid)
Ethane- 1,2 - diol (ethylene glycol)
217
What can we represent teryene as?
A repeat unit
218
What, basically, are the two things that we react to form terylene?
An acid and an alcohol
219
Why is soda lime (used in the reduction of decarboxylation of carboxylic acids) called this?
Soda —> NaOH
Lime —> Ca(OH)2
Soda-lime —> [Ca(OH)2/NaOH]
220
Why is the alkane formed one less carbon than the carboxylic acid during decarboxylation?
Since CO2 is removed
221
What do we do when asked to explain acid chloride formation?
Choose any of the following reagents:
-PCl4
-PCl5
-SOCl2
222
CH3CONH2
Ethanamide
223
Ethanamide
CH3CONH2
224
Why is heating the acid or its ammonium salt with urea at 120 degrees the better method for the formation of amides?
Since the produce are gases, making them easy to separate as they naturally escape
225
What is the preferred method for the formation of acid chlorides and why?
Using SOCl2 as a reagent
The by-products are easier to separate (SO2 and HCl are gases)
226
How are carboxylic acids produced from acid chlorides?
By hydrolysing them at room temperature
227
What’s more important when we consider boiling points - chain length or bonding?
Bonding
228
Arrange the following in order of increasing boiling point
Propan-1-ol, butane, ethanoic acid, propanal, propane
Propane
229
Why does butane have a higher boiling point than propane?
Longer chain alkane = more van der Waal forces
230
What has the highest boiling point - butane or propanal, and why?
Propanal
Permanent dipole = forms dipole forces
231
What has the highest boiling point - propan-1-ol or propanal, and why?
Propan-1-ol forms hydorgen bonds, Propanal doesn’t
232
Can aldehydes and ketones form hydrogen bonds?
Not with themselves, only with water
233
What has the highest boiling point - propan-1-ol or ethanoic acid, and why?
Ethanoic acid
Forms 2 hydrogen bonds
234
Catalyst for the base catalysed hydrolysis reaction of amides and nitriles
NaOH
235
Issue with HCl gas
Toxic
236
How do alkalis cause more damage than acid when spilled on clothes made from polyesters?
It hydrolyses the fibres
237
How many ways of naming amines are there?
2
238
Type of HCl specifically used to generate a free acid when forming a carboxylic acid from a nitrile
aq
239
How do we convert between moldm^-3 and gdm^-3?
Moldm-3 to gdm-3
xMr
gdm-3 to moldm-3
Divide by Mr
240
How would the hydrolysis of esters be base catalysed?
With NaOH
241
How would the hydrolysis of esters be acid catalysed?
With HCl
242
How could CH3COONa be represented in the base catalysed reaction of the hydrolysis of amides and nitriles?
CH3COO-
243
Aromatic carboxylic acid
Wheee the -COOH group is directly attached to the benzene ring
244
How do we go from CH3COOH to CH2ClCOOH?
Cl2
Room temperature + UV
245
What do we show when something undergoes hydrolysis with NaOH?
The O-Na+
eg: CH3CH2COO-Na+
246
How does an aromatic carboxylic acid salt appear and how does the final acid appear? Why?
Salt - colourless solution
Acid - white precipitate (insoluble in water)
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Why can’t we use NaOH to remove the HCl when reacting phenol and CH3COCl?
The CH3COCl would react preferably with the NaOH
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What happens when you react an amide and NaOH?
Na+O- from NH2
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Which is a weaker acid - phenol or carboxylic acid? Explain
Phenols are weaker acids than carboxylic acids since the delocalisation of the negative charge is less in the phenoxide ion than the carboxylate ion
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What do we show when showing the hydrolysis reaction of an ester and why?
Show it reacting with NaOH since its base catalysed (don’t just show it reacting with water)
