Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Chemistry Module 4 > 14.2 Reactions of Alcohols > Flashcards

14.2 Reactions of Alcohols Flashcards

1
Q

Describe how alcohols combust.

A

They can burn completely in a plentiful supply of oxygen to produce carbon dioxide and water.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Is the combustion of alcohols exothermic or endothermic?

A

Exothermic, releasing a large quantity of energy in the form of heat. As the number of carbon atoms in the alcohol chain increases, the quantity of heat released per mole also increases

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Which types of alcohols can be oxidised by an oxidising agent?

A

Primary and secondary alcohols

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What is the usual oxidising mixture used for alcohols?

A

Solution of potassium dichromate (VI) (K2Cr2O7), acidified with dilute sulfuric acid (H2SO4)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What can primary alcohols be oxidised to form?

A

Either aldehydes or carboxylic acids

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What does the product of the oxidation reaction of a primary alcohol depend on?

A

The reaction conditions used, and how long the product is left within the beaker

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Can carboxylic acids be further oxidised?

A

No

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Can aldehydes be further oxidised?

A

Yes, to carboxylic acids

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What is the method for oxidising alcohol to produce an aldehyde?

A

Gently heat a primary alcohol with acidified potassium dichromate

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What must you do to an aldehyde to ensure that it is not further oxidised?

A

Distill the aldehyde out of the reaction mixture as it forms

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What happens to the dichromate(VI) ions during the oxidation of an alcohol to produce an aldehyde?

A

Change colour from orange to green

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

How many moles of an oxidising agent need to be used to produce an aldehyde?

A

1

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

How do you oxidise an alcohol to produce a carboxylic acid?

A

Heat a primary alcohol strongly under reflux, with an excess of acidified potassium dichromate(VI)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Why do you use an excess of acidified potassium dichromate to produce a carboxylic acid?

A

To ensure that all of the alcohol is oxidised

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Why do you heat an alcohol under reflux when producing carboxylic acid?

A

To ensure that any aldehyde formed initially in the reaction also undergoes oxidation to the carboxylic acid.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

How many moles of oxygen do you use when oxidising an alcohol to produce carboxylic acid?

17
Q

What can secondary alcohols be oxidised to produce?

18
Q

What can ketones be further oxidised to produce?

A

It is not possible to further oxidise ketones using acidified dichromate(VI) ions.

19
Q

How do you ensure that the oxidation of an alcohol to form a ketone is done to completion?

A

Heat the alcohol under reflux with the oxidising mixture.

20
Q

What happens to dichromate ions during the oxidation of a secondary alcohol?

A

Changes from orange to green

21
Q

How many moles of an oxidising agent is used to oxidise a secondary alcohol?

22
Q

What can tertiary alcohols be oxidised to produce?

A

Tertiary alcohols do not undergo oxidation reactions.

23
Q

What is a dehydration reaction?

A

Any reaction whereby a water molecule is removed from the starting material

24
Q

How do you dehydrate an alcohol?

A

Heat it under reflux in the presence of an acid catalyst (such as sulfuric acid or phosphoric acid).

25
Q

What catalysts are used to dehydrate an alcohol?

A

Concentrated sulfuric acid (H2SO4) or concentrated phosphoric acid (H3PO4).

26
Q

What is the product of a dehydration reaction of an alcohol?

27
Q

What do alcohols react with to form haloalkanes?

A

Hydrogen halides

28
Q

What is produced when an alcohol reacts with a hydrogen halide?

A

Haloalkanes

29
Q

How is a haloalkane produced?

A

-Alcohol is heated under reflux with sulfuric acid and a sodium halide, which produces hydrogen bromide.
-The hydrogen bromide forms reacts with the alcohol to produce the haloalkane

30
Q

Write the equation that states how a hydrogen halide is formed, in order to produce a haloalkane (make the halide bromine)

A

NaBr (s) + H2SO4 (aq) –> NaHSO4 (aq) + HBr (aq)

31
Q

What is the overall equation for Propan-2-ol reacting with Sodium Bromide?

A

CH3CHOHCH3 + NaBr + H2SO4 –> CH3CHBrCH3 + NaHSO4 + H2O

32
Q

What is Tollen’s reagent used for?

A

Distinguishing aldehydes from ketones

33
Q

How can you use Tollen’s reagent to distinguish aldehydes from ketones?

A

-Ketones do not react with Tollen’s reagent,
-With an aldehyde, the Ag+ ion is reduced to Ag forming a silver film

34
Q

What happens to the aldehyde as it reacts with Tollen’s reagent?

A

It is oxidised to a carboxylic acid

35
Q

What is Fehling’s solution used for

A

Distinguishing aldehydes from ketones

Chemistry Module 4 (11 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions