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Chem Unit 4 > 4.3 Alcohols and Phenols > Flashcards

4.3 Alcohols and Phenols Flashcards

1
Q

What is the difference between a primary, secondary and tertiary alcohol?

A

If the carbon atom the OH group is bonded to is bonded to only one other carbon it is a primary alcohol
If the carbon the OH group is bonded to is bonded to two other carbons it is a secondary alcohol
If the carbon atom the OH group is bonded to is bonded to three carbons it is a tertiary alcohol

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2
Q

What type of reaction can a halogenoalkane undergo to form an alcohol?

A

nucleophilic substitution

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3
Q

What reactant and conditions are required to form ethanol from bromoethane?

A

Warm aqueous sodium hydroxide NaOH

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4
Q

What acts as the nucleophile in the reaction between chloroethane and warm aqueous sodium hybdroxide?

A

The hydroxide ion in the from the sodium hydroxide: OH-

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5
Q

What is the classification of the alcohol formed if 2-bromo-2-methylbutane undergoes nucleophilic substitution with KOH?

A

tertiary alcohol

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6
Q

Reactants and conditions required for the formation of a hydroxynitrile from an aldehyde/ ketone?

A

Potassium or sodium cyanide is added to sulfuric acid to produce hydrogen cyanide
temperature 20C

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7
Q

Why is the hydrogen cyanide not added directly to an aldhehyde/ ketone for a nucleophilic addition reaction?

A

hydrogen cyanide is a very poisonous gas

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8
Q

Name the type of reaction for the formation of alcohols from aldehydes and ketones

A

reduction

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9
Q

Draw and name the mechanism for the formation of 1-hydroxypropanenitrile from ethanal and hydrogen cyanide

A

nucleophilic add
(polarisation bet c&double bond o - cn intermediate lonepair on o and onto extra H+ -> prod)

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10
Q

The classification of the alcohols formed by the reduction of aldehydes and ketones?

A

aldehydes will be reduced to primary alcohols
ketones will be reduced to secondary alcohols

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11
Q

Give a reducing agent for the reduction of aldehydes and ketones to alcohols

A

NaBH4 dissolved in water with methanol

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12
Q

Chemical equation for the reduction of propanone to propan-2-ol

A

CH3COCH3 + 2[H] -> CH3C(OH)HCH3

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13
Q

Name the mechanism for the reduction of propanal to propan-1-ol

A

Nucleophilic addition

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14
Q

Reagent used to reduce carboxylic acids to alcohols

A

LiAlH4

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15
Q

Why is Na BH4 used for the reduction of aldehydes and ketones but not for carboxylic acids?

A

NaBH4 is not reactive enough to reduce carboxylic acids

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16
Q

Why are primary and secondary alcohols useful for organic sysnthesis rections?

A

The -OH functional group is able to react with various different compounds

17
Q

What type of organic product is produced in the reaction between alcohols and hydrogen halides?

A

Halogenoalkanes

18
Q

What catalyst is required for the reaction of primary and secondary alcohols with hydrogen chloride?

A

anhydrous zinc chloride

19
Q

What are the reagents required for the reaction of ethanol to form bromoethane?

A

Instead of directly adding hydrogen bromide, ethanol requires a mixture of potassium or sodium bromide and conc sulfuric acid. This will produce the hydrogen bromide which will react with ethanol to form bromoethane.

20
Q

What reagents are req to replace the -OH group with an iodine atom?

A

Sodium or potassium iodide is reacted with conc phosphoric acid, producing hydrogen iodide which reacts with the alcohol replacing the -OH group with an iodine atom

21
Q

Name for the product pf the reaction between 2-methylbutane-1,3-diol and excess hydrogen bromide?

A

1,3-dibromo-2-methylbutane

22
Q

The mechanism for the reaction between acyl chlorides and alcohols

A

nucleophilic addition-elimination

23
Q

drawthe mechanism for the rctn between ethanoyl chloride and methanol

A

dipole between C double bond O in ethanoyl chloride lone pair on O in CH3OH attacks slightly +ve carbon, intermediate attaches to carbon, O+ve so curly arrow from line bet H to O+, one of the lone pairs in -ve O(ethanoyl chloride) reforms double bond curly arrow from line bet C to Cl end prod then ch3-c=o(-o-ch3) +HCl

24
Q

What is formed when an alcohol reacts with a carboxylic acid?

A

An ester

25
Q

Functional group of an ester

A

-COO-

26
Q

What condition and catalyst id req for an esterification rctn?

A

The alcohol and carboxylic acid must be heated in the presence of a strong acid catalyst e.g. conc sulfuric acid

27
Q

Chemical eqn for the rctn between ethanoic acid and ethanol

A

CH3COOH + CH3CH2OH -> CH3COOCH2CH3 + H2O

28
Q

Name the ester formed in the rctn between butanoic acid and propanol

A

Propyl butanoate

29
Q

Identifying properties of esters

A

Sweet smelling often used in flavourings and perfumes, low boiling points, good solvents for other polar molecules

30
Q

What is a phenol?

A

Aromatic alcohol consisting of a benzene ring and an -OH alcohol group.

31
Q

Acidity of a phenol?

A

Phenol is very weakly acidic between pH 5 and 6

32
Q

What is observed when phenol reacts with bromine?

A

The bromine water will decolourise and a white ppt will form

33
Q

Why does phenol generally react more readily than benzene?

A

The increased reactivity of phenol is due to the lone pair of electrons on the oxygen atom delocalised into the ring structure increasing the electron density of the ring making it more susceptible to attack from electrophiles

34
Q

Considering acidity of phenol does it react with NaOH or Na2CO3?

A

Phenol will react with NaOH but since it is only weakly acidic it will not react with Na2CO3

35
Q

Name of the product formed when phenol reacts with ethanoyl chloride?

A

Phenyl ethanoate

36
Q

Chemical equation for the rctn between phenol and ethanoyl chloride?

A

C6H5OH + CH3COCl -> CH3COOC6H5 +HCl

37
Q

Chemical eqn for the rctn between phenol and bromine

A

C6H5OH + 3Br2 -> C6H2Br3OH + 3HBr

38
Q

Test for phenols

A

Aqueous ferric chloride (FeCl3) can be used to test for the presence of phenols, compounds containing phenols will cause solution to turn a vivid purple, blue, green or red colour - depending on the nature of the phenol

39
Q

Observed color change when ferric chloride is added to phenol.

A

On addition of ferric chloride the solution will turn a vivid violet-purple colour

Chem Unit 4 (8 decks)

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