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WJEC Chemistry > Alcohols > Flashcards

Alcohols Flashcards

1
Q

Define Hydrolysis

A

Decomposition of a compound by reaction with water.

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2
Q

Define Alkaline Hydrolysis

A

Hydrolysis: splitting compound with elements of water, Alkaline: relating to an alkali/alkali metal/base (pH>7) Alkali metals are the first column Li, Na, K, etc

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3
Q

Define Reagent

A

Substance used in a chemical reaction to detect, measure, examine or produce other substances

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4
Q

What is formed from the alkaline hydrolysis of a halogenalkane?

A

An Alcohol (OH replaces the Halogen via Nucleophilic Substitution)

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5
Q

What is formed from adding NaOH(aq) and heat to a Halogenalkane?

A

An Alcohol (OH replaces the Halogen via Nucleophilic Substitution)

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6
Q

What is formed from Nucleophilic Substitution of a Halogenalkane?

A

An Alcohol (OH replaces the Halogen via Nucleophilic Substitution)

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7
Q

An alcohol is formed using NaOH(aq) and heat from what?

A

A Halogenalkane (OH replaces the Halogen via Nucleophilic Substitution)

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8
Q

An Alcohol is formed using Nucleophilic Substitution from what?

A

A Halogenalkane (OH replaces the Halogen via Nucleophilic Substitution)

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9
Q

What mechanism occurs in the alkaline hydrolysis of Halogenalkane?

A

Nucleophilic Substitution to form an Alcohol

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10
Q

What mechanism occurs when NaOH(aq) and heat are added to a Haolgenalkane?

A

Nucleophilic Substitution occurs to form an Alcohol

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11
Q

Write a balanced equation and name all reagents and conditions to form an Alcohol from a Halogenalkane

A

CH3CH2Br + OH- ->
CH3CH2OH + Br-
Reagent: NaOH(aq)
Condition: Heat

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12
Q

Define Reduction

A

A half reaction in which a chemical species decreases it’s oxidation number (usually by electron gain)

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13
Q

Define Reducing Agent

A

A Reducing Agent donates electrons and is itself oxidised

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14
Q

What are the reagents and conditions for the formation of alcohols from carbonyls?

A

Just a Reducing Agent: NaBH4

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15
Q

NaBH4 is used to form a Secondary Alcohol from what?

A

A Ketone is reduced by NaBH4 to form a Secondary Alcohol

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16
Q

NaBH4 is used to form a Primary Alcohol from what?

A

An Aldehyde is reduced by NaBH4 to form a Primary Alcohol

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17
Q

A Carbonyl is treated with NaBH4 to form what?

A

Either a Primary or a Secondary Alcohol depending on whether the Carbonyl is an Aldehyde or Ketone respectively.

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18
Q

A Secondary Alcohol will be formed from the reduction of what?

A

Only a Ketone forms a Secondary Alcohol by reduction (Haloalkanes can form them by Hydrolyis) Both Aldehydes and Carboxylic Acids reduce to form a Primary Alcohol

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19
Q

NaBH4 is used to form a Primary Alcohol from what?

A

An Aldehyde is reduced by NaBH4

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20
Q

What are the reagents and conditions to form an Alcohol from a Carboxylic Acid?

A

LiAlH4 in Dry Ether acts as a Reducing Agent on the Carboxylic acid forming a Primary Alcohol
(NaBH4 does not work, as an even stronger reducing agent is needed)

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21
Q

LiAlH4 with a Carboxylic acid forms what?

A

A Primary Alcohol is the result of reduction by the LiAlH4 of the Acid

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22
Q

An Alcohol is formed with LiAlH4 from what?

A

A Carboxylic Acid is reduced by LiAlH4 to form a Primary Alcohol

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23
Q

How many ways are the to form an Alcohol?

A 
Five Ways:
Alkaline Hydrolysis of a Haloalkane
Reduction of an Aldehyde
(But not a Ketone)
Reduction of a Carboxylic Acid
Electrophilic addition from an alkene
Diazotisation of an amine
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24
Q

How can a Primary Alcohol be formed?

A 
Five Ways:
Alkaline Hydrolysis of a Haloalkane
Reduction of a Carbonyl
Reduction of a Carboxylic Acid
Electrophilic addition from an alkene
Diazotisation of an amine
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25
How can a Secondary Alcohol be formed?
Two Ways: Alkaline Hydrolysis of a Haloalkane Reduction of a Ketone (But not an Aldehyde)
26
How can a Tertiary Alcohol be formed?
Alkaline Hydrolysis of a Haloalkane is the only way | The Carbon attached to the Halogen has to have 3 R groups for this to occur
27
Draw Alkaline Hydrolysis of a Halogen Alkane
``` Br= any halogen R= carbon chain/H group ``` ``` C-Br have (d+) and (-) respectively, C has 3 other R groups, HO- curvy-> C opposite to Br(d-), from C-Br bond curvy-> Br(d-), -------Across the Arrow------- Intermediate both dotted bond, All in straight brackets (-) sign -------Across the Arrow------- Br- formed separately OH bonded opposite Br original ```
28
Draw formation of Alcohol from Haloalkane
``` Br= any halogen R= carbon chain/H group ``` ``` C-Br have (d+) and (-) respectively, C has 3 other R groups, HO- curvy-> C opposite to Br(d-), from C-Br bond curvy-> Br(d-), -------Across the Arrow------- Intermediate both dotted bond, All in straight brackets (-) sign -------Across the Arrow------- Br- formed separately OH bonded opposite Br original ```
29
Draw Haloalkane reacting woth NaOH(aq) in heat
``` Br= any halogen R= carbon chain/H group ``` ``` C-Br have (d+) and (-) respectively, C has 3 other R groups, HO- curvy-> C opposite to Br(d-), from C-Br bond curvy-> Br(d-), -------Across the Arrow------- Intermediate both dotted bond, All in straight brackets (-) sign -------Across the Arrow------- Br- formed separately OH bonded opposite Br original ```
30
Draw formation of Alcohol using Nucleophilic Substitution Mechanism
``` Br= any halogen R= carbon chain/H group ``` ``` C-Br have (d+) and (-) respectively, C has 3 other R groups, HO- curvy-> C opposite to Br(d-), from C-Br bond curvy-> Br(d-), -------Across the Arrow------- Intermediate both dotted bond, All in straight brackets (-) sign -------Across the Arrow------- Br- formed separately OH bonded opposite Br original ```
31
NaOH(aq) and heat are use to form an alcohol, draw this.
``` Br= any halogen R= carbon chain/H group ``` ``` C-Br have (d+) and (-) respectively, C has 3 other R groups, HO- curvy-> C opposite to Br(d-), from C-Br bond curvy-> Br(d-), -------Across the Arrow------- Intermediate both dotted bond, All in straight brackets (-) sign -------Across the Arrow------- Br- formed separately OH bonded opposite Br original ```
32
What is the product of an Alcohol reacting with a Carboxylic Acid?
An Ester and Water
33
An Ester is formed from a Carboxylic Acid and what?
An Acohol
34
An Ester is formed from an Alcohol and what?
Either a Carboxylic Acid | or an Acyl Chloride
35
What reagents and conditions are used for an Alcohol reacting with a Carboxylic Acid?
Reagent=Catalyst=Conc H2SO4 | Conditions=Heat
36
What reagents and conditions are used when an Ester is formed from a Carboxylic Acid?
Reagent=Catalyst=Conc H2SO4 | Conditions=Heat
37
What reagents and conditions are used when an Ester is formed from an Alcohol
If reacted with a Carboxylic Acid: Reagent=Catalyst=Conc H2SO4 Conditions=Heat If reacted with an Acyl Chloride: The Ethanoyl Chloride should be Anydrous and a fume cupboard should be used
38
In Esterification using a Carboxylic Acid and an Alcohol why is Conc H2SO4 used?
Any strong H+ will act as a catalyst here but they use Conc H2SO4 because it can also act as a Hydrating agent, removing H2O from the equilibrium which will shift the equilibrium to the right and increase the yield of Ester
39
H2SO4 acts as what in the Esterification of a Carboxylic Acid and Alcohol?
A Catalyst and a Hydrating Agent
40
Define Hydrating Agent
A Species that causes Hydration; the incorporation of molecular water into a complex molecule with elements of another species
41
Define Catalyst
A substance, usually used in small amounts relative to the reactants, that modifies and increases the rate of a reaction without being consumed in the process.
42
Give an equation for an Ester being formed from an Alcohol
With a Carboxylic Acid: RCOOH+R1-OH -> RCOOR1+H2O With an Acyl Chloride CH3COCl+ROH -> CH3COOR+HCl
43
Give an equation for an Ester being formed from a Carboxylic Acid
RCOOH+R1-OH -> RCOOR1+H2O With Conc H2SO4 and heat
44
What is the product of an Alcohol and an Acyl Chloride?
An Ester and HCl
45
An Ester is formed from Ethanoyl Chloride and what?
An Alcohol
46
What Reagents and Conditions are used for an Alcohol reacting with Ethanoyl Chloride?
Anhydrous conditions are needed for the Ethanoyl Chloride, as it is Hydrolysed in the presence of H2O forming HCl gas (corrosive)
47
What type of reaction occurs when an alcohol and Ethanoyl Chloride react?
Esterification (sometimes called Ethanoylation)
48
Give an Equation for an Ester being formed from an Acyl Chloride
CH3COCl+ROH -> CH3COOR+HCl
49
Give an equation for an alcohol reacting with an Acyl Chloride
CH3COCl+ROH -> CH3COOR+HCl
50
Dehydration of an Alcohol results in what?
An Alkene and H2O
51
Alcohol reacts with Conc H2SO4 to form what?
An Alkene and H20
52
What type of reaction occurs when Conc H2SO4 is added to an Alcohol?
A Dehydration reaction | If a Carboxylic Acid is also present, Esterification can occur
53
A Non-Primary Alcohol can form up to 3 different products, why is this?
When Dehydration of an Alcohol occurs, the OH group is removed along with a H from the Carbon attached to the Carbon that is attached to the OH Draw and check with Butan-2-ol
54
3 possible products can be formed from adding Conc H2SO4 to what?
A Secondary or Tertiary Alcohol
55
Show Ethan-1-ol being dehydrated by Conc H2SO4
CH3CH2OH -> CH2=CH2+H2O
56
Show Butan-2-ol being dehydrated by Conc H2SO4
CH3CH2CH(OH)CH3 -> CH3CH2CH=CH2 Or CH3CH2CH(OH)CH3 -> CH3CH=CHCH3 E and Z
57
Define Distillation
The process of purifying a liquid by boiling it and then condensing it's vapours
58
Define Oxidation
Oxidation is the gain of oxygen or the loss of Hydrogen Or Oxidation is the loss of electrons
59
Define Oxidising Agent
An Oxidising Agent is a species that causes oxidation in another and is itself reduced
60
What results from the Oxidation of an Alcohol?
If the Alcohol is Primary an Aldehyde or Carboxylic Acid is formed, but if it is Secondary a Ketone is formed. (An Aldehyde will be formed only if the Alcohol is heated gently and distilled off before it oxidises further to a Carboxylic Acid)
61
What are the reagents and conditions needed to oxidise an Alcohol?
Acidified Dichromate VI (Cr2O7/H+) For Aldehyde: warm gently and distill off before further oxidised For Carboxylic Acid: Heat Under Reflux from Alcohol or just heat further from Aldehyde For Ketone: Heat Under Reflux
62
What are the reagents and conditions needed to form an Aldehyde?
A Primary Alcohol Needs to be Warmed Gently with Acidified Dichromate VI and the aldehyde needs to be distilled off before it oxidises further to a Carboxylic Acid
63
What is the observation noted when an alcohol is oxidised to a Carbonyl or Carboxylic Acid?
Solution goes from Orange to Green as the Cr ion is reduced from +6 oxidation state to +2
64
What reagents and conditions are needed to form a Carboxylic Acid from an Aldehyde?
Acidified Dichromate VI and Heat
65
When forming an Aldehyde from a Primary Alcohol how is the Aldehyde removed and why?
It is removed via distillation as it's boiling point is lower due to only having Van Der Waals forces which are weaker than the extra Hydrogen bonding the Carboxylic Acid and Alcohol both have more of due to their OH group
66
Why can a ketone not be oxidised further from an alcohol?
In order to form a carboxylic acid from a secondary alcohol C-C bond would need to be broken, but they are too strong
67
A Ketone is formed by Oxidising what?
A Secondary Alcohol by Heating under reflux with Acidified Dichromate VI
68
An Aldehyde is formed by oxidising what?
A Primary alcohol with Acidified Dichromate VI and warming gently
69
A Carboxylic Acid is formed by Oxidising what?
An Alcohol by Heating Under Reflux or an Aldehyde by Heating further. Both with Acidified Dichromate VI
70
How are alcohols formed from an alkene?
``` Electrophilic Addition 60atm H2O H3PO4 330°C ```
71
How can an amine be converted to an alcohol?
Diazotisation KNO2/HCl (HNO2) Warm Produces N2 gas
72
When an amine is converted to an alcohol what is the bi product?
N2 gas
73
What are the conditions to convert an alcohol to an alkene?
Either 1) excess H2SO4 conc & 170°C Or 2) pass alcohol vapour over Al2O3 at 360°C
74
What are two large scale uses for alcohols?
As a solvent | As a fuel
75
Why are alcohols good fuels?
Clean flame Complete oxidation Lots of energy evolved
76
Where is ethanol widely used as a fuel?
In S America from fermentation of sugar wastes
77
How are halo alkenes formed from alcohols?
Nucleophilic substitution | Using either PCl5 or HBr (KBr H2SO4(l) )
78
What are the conditions used to convert an alcohol to a chloralkane?
PCl5 Room temp Anhydrous
79
What are the conditions needed to convert an alcohol to a bromo alkane?
KBr(s) H2SO4(l) (HBr) | Warm

WJEC Chemistry (7 decks)

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