4.2.1: Alcohols Flashcards

1
Q

What is the functional group of an alcohol?

A

Hydroxyl group -OH

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2
Q

What is the general formula of an alcohol?

A

Cn H2n+1 OH

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3
Q

How do you name alcohols (one prefix, one suffix)?

A

Hydroxyl- OR -ol

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4
Q

What kind of intermolecular forces do alcohols have? Why?

A

Hydrogen bonding, due to the electronegativity difference in the OH bond

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5
Q

How do alcohols’ melting point and boiling point compare to other hydrocarbons’ of similar C chain lengths? Why?

A

Higher, because they have hydrogen bonding (strongest type of intermolecular force) → stronger than London forces

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6
Q

Are alcohols soluble in water? Why does solubility depend on chain length?

A

Soluble when short chain - OH hydrogen bonds
to hydrogen bond in water
Insoluble when long chain - non-polarity of C-H
bond takes precedence

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7
Q

What makes an alcohol primary?

A

OH group is attached to C with 2 H atoms and 1 alkyl group

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8
Q

What makes an alcohol secondary?

A

OH bonded to C atom with 1 H atom and 2 alkyl groups

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9
Q

What makes an alcohol tertiary?

A

C bonded to OH is bonded to three other C atoms

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10
Q

Write an equation for the combustion of ethanol

A

C2H5OH (l) + 3O2 (g) → 2CO2 (g) + 3H2O (l)

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11
Q

What forms if you partially oxidise a primary alcohol?

A

An aldehyde

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12
Q

What conditions are needed to partially oxidise a primary alcohol?

A

Dilute sulphuric acid, potassium dichromate (VI), distill product as it’s produced, gentle heating

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13
Q

Write an equation for the partial oxidation of ethanol

A

CH3CH2OH (l) + [O] → CH3CHO (g) + H2O (l)

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14
Q

What forms if you fully oxidise a primary alcohol?

A

A carboxylic acid

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15
Q

What conditions are needed to fully oxidise a primary

alcohol?

A

Concentrated sulphuric acid, potassium dichromate (VI), reflux, strong heating

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16
Q

Write an equation for the full oxidation of ethanol

A

CH3CH2OH (l) + 2[O] → CH3COOH (g) + H2O (l)

17
Q

What forms if you oxidise a secondary alcohol?

A

A ketone

18
Q

What conditions are needed for the oxidation of a secondary alcohol?

A

Concentrated sulphuric acid, potassium dichromate (VI), strong heating

19
Q

Write an equation for the oxidation of propan-2-ol.

A

CH3CH(OH)CH3 (l) + [O] → CH3COCH3 (g) + H2O (l)

20
Q

Is it possible to oxidise tertiary alcohol?

A

no

21
Q

What is a dehydration reaction?

A

A reaction where water is lost to form an

organic compound

22
Q

What are the products of dehydration reaction of alcohol?

A

Alkene and water

23
Q

What are the conditions required for dehydration of alcohol?

A

Concentrated sulfuric acid or concentrated phosphoric acid and 170°C

24
Q

What are the products of the halide substitution reaction with alcohol?

A

Haloalkane and water

25
Q

In what form is the halide used in halide substitution reaction?

A

In the form of hydrogen halide, e.g HBr

26
Q

How is hydrogen halide made in situ? Give examples

A

A salt is reacted with acid to form the hydrogen halide
E.g sodium bromide reacts with sulfuric acid to form HBr
When iodine is reacted phosphoric acid is used as
sulfuric acid oxidises iodide ions into iodine