Brainscape's Knowledge GenomeTM

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


See full index

chemistry > Alcohols phenols ethers > Flashcards

Alcohols phenols ethers Flashcards

You may prefer our related Brainscape-certified flashcards:
AP® Chemistry flashcards Periodic Table flashcards Chemistry 101 flashcards Organic Chemistry 101 flashcards
1
Q

The bond angle in alcohols is slightly ____ than tetrahedral angle

A

less - due to repulsion between unshared electrons of oxygen

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

The bond angle in ethers is slightly ____ than tetrahedral angle

A

more - repulsive interaction between bulky R groups

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

How are alcohols prepared from alkenes

A
  1. acid catalysed hydration - alkenes react with water in presence of acid as a catalyst. MKR
  2. hydroboration oxidation - diborane + alkenes give trialkyl borane which on reaction with hydrogen peroxide in the presence of aq NaOH gives alcohol. AMKR
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

How are alcohols prepared from carbonyl compounds?

A
  1. Reduction of aldehydes and ketones - addition of H2 in presence of catalyst - Pd Pt Ni NaBH4 LiAlH4
  2. Reduction of carboxylic acid - reduced to primary alcohol with excellent yield by LiAlH4
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

How are alcohols prepared from acids commercially

A

Converting to esters by adding R’OH in acid presence and then converting ester to alcohol by catalytic hydrogenation. (H in presence of catalyst)

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

What type of alcohol do aldehyde and ketone give on reduction?

A

Primary alcohol - aldehyde

Secondary alcohol - Ketone

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

What is the reaction mechanism from prep from Grignard reagent

A

Nucleophilic addition. hydrolysis

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

What type of alcohols are produced when we use Grignards reagent to prepare them

A

primary alcohol - methanal
secondary alcohol - aldehydes
tertiary alcohol - ketones

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

what is another name for phenol

A

carbolic acid

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

Name the 4 methods that can be used to prepare phenol in the lab

A

From haloarenes, From benzene sulphonic acid, From diazonium salts, From cumene

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

How to prep phenol from chlorobenzene

A

Chlorobenzene fused with NaOH at 623K and 320 atm gives sodium phenoxide. On acidification with HCl gives phenol

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

How to prep from benzene sulphonic acid

A

Benzene is sulphonated with oleum and benzene sulphonic acid so formed is converted to sodium phenoxide on heating with molten sodium hydroxide. Acidification of sodium salt gives phenol.

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

How to prep phenol from diazonium salts

A

amine + NaNO2 + HCl at 273-278 K gives diazonium salt. Diazonium salts are hydrolysed to phenols by warming with water or treating with dilute acids

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

How to prep phenol from cumene

A

Cumene oxidised in presence of air to cumene hydroperoxide. converted to phenol and acetone by treating with dilute acid.

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

cumene IUPAC name

A

isopropylbenzene

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

Why is bp of alcohols and phenols higher than other classes of compounds

A

intermolecular H-bonding

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What id trend of solubility on alcohols and phenols

A

decrease with increase in size

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Which bond has to break on alcohols from them to act as nucleophiles

A

O-H bond

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

why are alcohols acidic

A

polar nature oh o-h bond

20
Q

what is the trend of acidic strength on alcohols

A

primary>secondary>tertiary

21
Q

why are alcohols bases

A

presence of unshared electron pairs on oxygen

22
Q

How are esters formed from alcohols and phenols

A

Carboxylic acid/acid anhydride: conc H2SO4, reversible, ROH +R’COOH = ROCOR’ +H20. water is removed as soon as it is formed.
Acid chloride: presence of base (pyridine) to neutralise HCl formed.

23
Q

What is acetylation

A

introduction of acetyl group (CH3CO) in alcohols and phenols

24
Q

Acetylation of salicylic acid gives what

A

Asprin

25
Q

What is Lucas test

A

Tertiary halides from alcohol - turbidity immediately (white ppt)
Secondary alcohols - turbidity after a few minutes
Primary alcohol - no turbidity at room temp

26
Q

How do alcohols become alkenes

A

dehydration in presence of protic acids (H2SO4, H3PO4) or catalysts such as anhy ZnCl2, alumina

27
Q

what are the conditions under which alcohols become alkenes

A

ethanol - H2SO4 ,443K
2-propanol - 85% H3PO4, 440K
tertiary - 20% H3PO4, 358K

28
Q

How to isolate aldehyde when prepared from alcohol

A

CrO3 in anhydrous medium is used as the oxidisng agent

29
Q

How to get carboxylic acid directly from alcohoL

A

use strong oxidising agent like potassium permanganate

30
Q

Reagents used when oxidising alcohol

A

aldehyde - PCC, ketone - CrO3

31
Q

what happens when we pass vapours of primary or secondary alcohol over heated copper at 573 K

A

primary becomes aldehyde, secondary becomes ketone, tertiary becomes alkene

32
Q

How to seperate ortho and para nitrophenol

A

steam distillation. o is steam volatile due to intramolecular hydrogen bonding and p is less volatile due to intermolecular hydrogen bonding

33
Q

What different products are obtained when we use dil HNO3 and conc HNO3 with phenol

A

dil - nitophenol , conc - picric acid (2,4,6 - Trinitrophenol)

34
Q

how to get better yield of picric acid

A

treat phenol with conc H2SO4 first to get 2,4 - disulphonic acid and then conc HNO3

35
Q

What are the different products we get on treating phenol with bromine in different conditions

A

in solvents with low polarity like CHCl3 or CS2 and at low temp - monobromophenols
with bromine water - 2,4,6-tribromophenol as white ppt

36
Q

What is kolbes reaction

A

when phenol is treated with NaOH it becomes phenoxide ion which is even more reactive. The ion + CO2 and acid gives 2- Hydroxybenzoic acid / salicylic acid

37
Q

What is Reimer Tiemann reaction

A

Phenol + CHCl3 +NaOH gives intermediate benzal chloride. On treating with alkali we get salicylaldehyde

38
Q

How to convert phenol to benzene

A

on heating with zinc dust

39
Q

How to convert phenol to benzoquinone

A

phenol + Na2Cr2O7 and H2SO4

40
Q

How to prep ethers

A

dehydration of alcohol-protic acid (413K for ethanol to ethoxyethane)
Williamson synthesis - alkyl halide + sodium alkoxide

41
Q

what is the reaction mechanism for prep of ethers from alcohols

A

SN2

42
Q

Why should we use primary alcohols for prep of ether

A

secondary and tertiary will follow SN1 rxn but elimination competes over substitution forming alkenes

43
Q

Which reactant in Williamson’s synthesis should be primary

A

Alkyl halide should be primary else elimination will happen. It follows Sn2 mechanism. Sodium alkoxide can be tertiary

44
Q

How to convert phenol to ether

A

Williamson’s synthesis. Add NaOH to give phenoxide ion and then add R-X

45
Q

How to cleave ethers

A

drastic conditions with excess of H-X where x = I, Br

46
Q

What ion do you get by protonating anisole

A

oxonium ion C6H5-O(+)H-CH3

chemistry (3 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions