Brainscape's Knowledge GenomeTM

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


See full index

Chemistry > 2.9 Alcohol > Flashcards

2.9 Alcohol Flashcards

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

alcohol can be classified into ?

A

primary

secondary

tertiary

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

CH3 CH2 CH2 OH

name
class

A

propan - 1 - ol

primary

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

CH3 CH2 CH(OH) CH3

name
class

A

butan - 2 - ol

secondary

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

(CH3)3 OH

name
class

A

2-methylpropan-2-ol

tertiary

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

why alcohols are more reactive than alkanes?

A

C–OH bond is polarised

C slightly + is susceptible to attack by nucleophiles

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

reactions of alcohols

give 2

A
  1. combustion

2. metallic sodium

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

how ethanol is made

A

fermentation of sugar cain or grain

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q
  1. combustion of alcohols
A
  1. combustion
    alcohol burns to give CO2 and water
    burns with blue flame and little soot
    eq refers to note pg 2
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q
  1. reaction of alcohols with metallic sodium
A
  1. metallic sodium
    sodium very reactive
    forces hydrogen in -OH to behave like an acidic hydrogen
    sodium replaces hydrogen in this reaction to form hydrogen gas
    eq refers to notes pg2
    if excess ethanol is evaporated, sodium ethoxide ( ionic compound) is seen as a white solid
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

sodium and water

A

eq refer notes pg 2

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

sodium in water

A

flame and quite vigorous due to exothermic reaction which the heat reacted with h2 produced

effervescence

sodium hydroxide soluble is water

sodium floats

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

sodium in ethanol

A

no flame and less vigorous

effervescence by h2

sodium ethoxide seen as white solid and dissolves slowly as it pulls moisture from surrounding

sodium do not float

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

other than water and alcohol

what else react vigorously with sodium to produce bubbles

A

acid

write eq refer notes pg 3

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

propan - 1- ol when burns

eq

A

refer to notes pg 3

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

sodium and propan - 1 - ol

eq

A

refer to notes pg 3

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

types of reaction with alcohols

name 3

A

substitution

oxidation

dehydration / elimination

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

substitution of alcohols -OH substituted by a halogen atom

  1. formation of chloroalkane
eq
reagent
condition
product
reaction type 
observation

test for hydroxyl group presence in carboxylic acid

A

eq: refer to notes
reagent: solid phosphorus pentachloride
condition: room temp, dry test tube
product: chloroethane ( reactant : ehthanol )

reaction type : nucleophilic substitution

observation: steamy fumes ( HCL)

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

why dry test tube is used

A

avoid reaction btwn phosphorus pentachloride with water

to form steamy fumes

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

HCL is colourless gas but why appears as steamy fumes

A

reacted with moist air

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q
  1. formation of chloroalkane

reagent used to test for HCL gas

A

glass rod dipped in conc ammonia form white smoke

ammonium cloride

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

substitution of alcohols -OH substituted by a halogen atom

  1. formation of bromoalkane
eq
reagent
condition
product
reaction type 
observation
A

eq: refer to notes

reagent: sodium bromide plus 50 % conc sulphuric acid
( to prevent further oxidation of HBR to Br2 )

condition: heat under reflux
product: bromoethane ( reactant : ethanol )

reaction type : nucleophilic substitution

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

procedure to make bromoethane from ethanol

A
  1. place a mixture of water, NaBr and ethanol in a round bottom flask ( ensure even heating )
  2. slowly add conc sulfuric acid drop by drop to the mixture
  3. heat the mixture under reflux for 45 mins
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q
  1. formation of bromoalkane

why water is used

A

to dilute conc H2SO4

it will further oxidised HBr to Br2

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q
  1. formation of bromoalkane

what is reflux

A

continual boiling and condensing of a reaction mixture

without the contents of the flask boiling dry

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q
  1. formation of bromoalkane

distillation
to distil off crude bromoethane and collect the distillate at 95 and 105 degree celsius

draw diagram for distillation

A

refer to notes pg 5

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q
  1. formation of bromoalkane

distillation
to distil off crude bromoethane and collect the distillate at 95 and 105 degree celsius

why mixture is distilled off

A

to separate volatile substance from involatile sodium acid and salt

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q
  1. formation of bromoalkane

distillation
to distil off crude bromoethane and collect the distillate at 95 and 105 degree celsius

why distillate is immersed in cold water

A

bromoalkane is volatile

to prevent evaporation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q
  1. formation of bromoalkane

distillation
to distil off crude bromoethane and collect the distillate at 95 and 105 degree celsius

the distillate forms two layers
what is the orgainc layer

A

unreacted ethanol

1 - bromoethane ( desired product )

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q
  1. formation of bromoalkane

distillation
to distil off crude bromoethane and collect the distillate at 95 and 105 degree celsius

what is the inorgainc layer

A

HBr

water

residual ethanol

30
Q
  1. formation of bromoalkane

distillation
to distil off crude bromoethane and collect the distillate at 95 and 105 degree celsius

the two layers form in the distillate is separated using separating funnel

draw the diagram

A

refer notes pg 5

31
Q
  1. formation of bromoalkane

distillation
to distil off crude bromoethane and collect the distillate at 95 and 105 degree celsius

the two layers form in the distillate is separated using separating funnel

how the process is being done

A

add water to the separating funnel and shake
allow two layers to separate and discard the lower aq layers

repeat twice the washing with water
discard lower aq layer each time

32
Q
  1. formation of bromoalkane

distillation
to distil off crude bromoethane and collect the distillate at 95 and 105 degree celsius

the two layers form in the distillate is separated using separating funnel

why water is added

A

to remove residual alcohol as ethanol is soluble in water

33
Q
  1. formation of bromoalkane

distillation
to distil off crude bromoethane and collect the distillate at 95 and 105 degree celsius

the two layers form in the distillate is separated using separating funnel

then wash with ?

A

wash with sodium carbonate solution

carefully releasing the pressure at intervals

shake and discard aq layer

34
Q
  1. formation of bromoalkane

distillation
to distil off crude bromoethane and collect the distillate at 95 and 105 degree celsius

the two layers form in the distillate is separated using separating funnel

then wash with sodium carbonate solution

why sodium carbonate is used

A

to remove the acid which dissolved in organic layer

35
Q
  1. formation of bromoalkane

distillation
to distil off crude bromoethane and collect the distillate at 95 and 105 degree celsius

the two layers form in the distillate is separated using separating funnel

then wash with sodium carbonate solution

why pressure is periodically released?

A

to released the presence due to co2 form

36
Q
  1. formation of bromoalkane

distillation
to distil off crude bromoethane and collect the distillate at 95 and 105 degree celsius

the two layers form in the distillate is separated using separating funnel

then wash with sodium carbonate solution

run off the organic layer into small conical flask, then add a little ?

A

add anhydrous calcium chloride

swirl the mixture until clear

37
Q
  1. formation of bromoalkane

distillation
to distil off crude bromoethane and collect the distillate at 95 and 105 degree celsius

the two layers form in the distillate is separated using separating funnel

then wash with sodium carbonate solution

run off the organic layer into small conical flask, then add a little anhydrous calcium chloride.

what is the function of anhydrous calcium chloride?

A

a drying agent to remove trace of water

38
Q
  1. formation of bromoalkane

distillation
to distil off crude bromoethane and collect the distillate at 95 and 105 degree celsius

the two layers form in the distillate is separated using separating funnel

then wash with sodium carbonate solution

run off the organic layer into small conical flask, then add a little anhydrous calcium chloride.

why initially mixture is cloudy?

A

cloudiness means mixture is not dry due to presence of tiny water droplet in bromoethane

39
Q
  1. formation of bromoalkane

distillation
to distil off crude bromoethane and collect the distillate at 95 and 105 degree celsius

the two layers form in the distillate is separated using separating funnel

then wash with sodium carbonate solution

run off the organic layer into small conical flask, then add a little anhydrous calcium chloride.

decant the liquid into?

A

decant into a dry distillation flask

product is redistilled

40
Q
  1. formation of bromoalkane

distillation
to distil off crude bromoethane and collect the distillate at 95 and 105 degree celsius

the two layers form in the distillate is separated using separating funnel

then wash with sodium carbonate solution

run off the organic layer into small conical flask, then add a little anhydrous calcium chloride.

decant the liquid into distilled flask.

what is meant by decant?

A

pour off the liquid, leaving the solid behind

41
Q
  1. formation of bromoalkane

distillation
to distil off crude bromoethane and collect the distillate at 95 and 105 degree celsius

the two layers form in the distillate is separated using separating funnel

then wash with sodium carbonate solution

run off the organic layer into small conical flask, then add a little anhydrous calcium chloride.

decant the liquid into distilled flask.

why need to redistill?

A

to check the purity of bromoethane

temp 36 - 39 degree celcius

42
Q

substitution of alcohols -OH substituted by a halogen atom

  1. formation of iodoalkane
eq
reagent
condition
product
reaction type
A

eq: refer to notes
reagent: iodine, moist red phosphorus
condition: heat under reflux
product: iodoethane ( reactant: ethanol )

reaction type: nucleophilic substitution

43
Q

substitution of alcohols -OH substituted by a halogen atom

  1. formation of iodoalkane

why sodium iodide and 50% conc sulfuric aicd cannot be used as a reagent to convert ethanol to iodoethane

A

even 50 % H2SO4 will oxidise HI completely to I2

yield is very low

44
Q

another way to form chloroalkane

A

follow bromoethane

reagent: conc H2SO4 and NaCl

H2SO4 no longer 50% conc because Cl cannot be further oxidised

condition: heat under reflux

45
Q

oxidation reactions of alcohols

oxidising agent use

A

acidified K2Cr2O7

46
Q

oxidation reactions of alcohols

primary alcohols oxidised to ?

A

aldehyde and carboxylic acid

47
Q

oxidation reactions of alcohols

secondary alcohols oxidised to?

A

ketone

48
Q

oxidation reactions of alcohols

tertiary alcohols oxidised to?

A

nothing

cannot be oxidised

49
Q

oxidation reactions of alcohols

oxidation of primary alcohol to aldehyde

eq
reagent
condition
product
reaction type
observation
A

eq refer to notes

reagent: potassium dichromate (VI) solution and sulfuric acid ( to supply H+ so dichromate ( VI ) turns Cr3+ to green )
condition: distillation
product: ethanal ( reactant : ethanol, primary )

reaction type: oxidation

observation: orange solution turns green

50
Q

oxidation reactions of alcohols

oxidation of primary alcohol to aldehyde

draw diagram of distillation

A

refer notes pg 8

51
Q

oxidation reactions of alcohols

oxidation of primary alcohol to aldehyde

why distillation

A

to prevent further oxidation of aldehyde

distill off aldehyde as it forms

52
Q

oxidation reactions of alcohols

oxidation of primary alcohol to carboxylic acid

eq
reagent
condition
product
reaction type
observation
A

eq refer to notes

reagent: potassium dichromate (VI) solution and sulfuric acid ( to supply H+ so dichromate ( VI ) turns Cr3+ to green )
condition: heating under reflux
product: ethanoic acid ( reactant: ethanol, primary )

reaction type: oxidation

observation: orange turns green

53
Q

oxidation reactions of alcohols

oxidation of primary alcohol to carboxylic acid

heating under reflux

draw diagram

A

refer to notes pg 9

54
Q

oxidation reactions of alcohols

oxidation of primary alcohol

why H2SO4 is added slowly

A

reaction is exothermic

55
Q

oxidation reactions of alcohols

oxidation of primary alcohol

why is it necessary to cool the mixture while adding acid

A

to prevent mixture heating too rapidly

cause ethnanol to evaporate

56
Q

oxidation reactions of alcohols

oxidation of primary alcohol

purpose of anti bumping granules

A

prevent super heating/violent heating

effect known as bumping, very hazardous

57
Q

oxidation reactions of alcohols

oxidation of primary alcohol

why water bath is used rather than heating flask directly with bunsen flame

A

alcohol is flammable

uniform heating

58
Q

oxidation reactions of alcohols

oxidation of primary alcohol

after heating, ethanoic acid was separated and washed and dried with drying agent

finally purify the ethanoic aicid in a narrow temp range

what is the temp range?

A

117 to 119 degree celcius

59
Q

oxidation reactions of alcohols

oxidation of secondary alcohol to ketone

eq
reagent
condition
product
reaction type
observation
A

eq: refer to notes pg 11
reagent: potassium dichromate (VI) solution and sulfuric acid ( to supply H+ so dichromate ( VI ) turns Cr3+ to green )
condition: heating under reflux
product: propanone ( reactant: propan-2ol secondary

reaction type: oxidation

observation: orange to green

60
Q

why ketone and tertiary alcohol cannot be further oxidised?

A

during oxidation, hydrogen atom from OH- group and the one attached to the carbon atom of OH- are removed to produce water.

in tertiary alcohol, there is only one hydrogen atom from the carbon that is attached to OH-

is want to be oxidised, C—C bond needs to be broken which is impossible for ketone and tertiary alcohol

C—C bond is very strong, C—H is very easy to break

61
Q

how to comfirm presence of -OH bond in alcohol

give two tests

A

add Na. effervescence

add PCl5 dry. misty fumes

62
Q

how to distinguish primary and secondary alcohols from tertiary

A

add K2Cr2O7 / dilute H2SO4 . orange to green

63
Q

how to identify alcohol structural for alcohol

A

spectrometry analysis

64
Q

dehydration of alcohols

draw diagram

A

refer to note pg 12

65
Q

dehydration of alcohols

heat the granules gently and collect 4 test tubes of gas discarding the first one

why?

A

not the product

reaction has not taken place when heating just started

expantion of air due to heating

66
Q

dehydration of alcohols

why aluminium oxide granules are used

A

act as catalyst

67
Q

dehydration of alcohols

why the delivery tube needs to be removed from the water first before the source of heat is removed?

A

prevent suck back

test tube will crack and explode

68
Q

dehydration of alcohols

test flammability of gas collected

A

yellow flame

flammable

69
Q

dehydration of alcohols

bromine water i added into gas

A

reddish brown colour is decolourised

70
Q

dehydration of alcohols

acidified solution of potassium manganate ( VII ) is added to gas

A

purple colour is decolourised

71
Q

dehydration of alcohols

yellow flame
reddish brown colour is decolourised
purple colour is decolourised

what is the nature if the product?

A

alkene is a product of elimination

Chemistry (9 decks)

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