Exercise 9: PHENOLS

Question 1

organic aromatic compounds
wherein the hydroxyl group is
attached to a benzene ring

 considered as alcohols due to
their OH group, however,
differ in their chemical
behavior

Answer 1

PHENOLS

Question 2

PHENOLS  difference with alcohols
technically is due to the

Answer 2

phenyl ring

Question 3

PHENOLS
also known as

Answer 3

hydroxybenzene or carbolic acid

Question 4

PHENOLS is

Answer 4

toxic, colorless crystalline solid with sweet tarry odor

Question 5

Phenols usually employed as an

Answer 5

antiseptic and disinfectant

Question 6

also used in cosmetic formulations and manufacture of some
drugs (precursor)

Answer 6

PHENOLS

Question 7

generally have higher boiling points as compared to hydrocarbons
having the same molecular masses

mainly due to the intermolecular H-bonding in between the OH
groups

Answer 7

BOILING POINT

Question 8

boiling point  = number of C atoms increase

Answer 8

Increase

Question 9

governed by its ability to perform intermolecular H-bonding with
polar solvents

Answer 9

SOLUBILITY

Question 10

 H-bonds make it possible for the phenol to be - to the
water

however, an - attached to the
hydroxyl group decrease its solubility in water

Answer 10

slightly soluble

increase in the size of the aryl group

Question 11

ACIDITY
 acidic in nature due to its reactivity with active metals (e.g. sodium, potassium,
etc.) to form corresponding

 sp2 hybridized C of the benzene ring attached to the OH group functions as an
(decreases the electron density on the oxygen)

Answer 11

phenoxides

electron withdrawing group

Question 12

 due to the, phenoxide ions are more stable (phenols are more, than alcohols)

Answer 12

delocalization of the electrons in the benzene ring, acidic

Question 13

 in substituted phenols, its acidity - if an electron donating group is
attached to the ring and vice versa

Answer 13

decreases

Question 14

 diazotization of primary aromatic amines

Answer 14

SYNTHESIS OF PHENOLS

Question 15

 when a primary aromatic amine with nitrous acid (NaNO2 + HCl) at ~5°C,
is formed

 these diazonium salts are highly reactive and upon warming with water, will be
hydrolyzed in to

Answer 15

benzene diazonium chloride

phenol

Question 16

primary aromatic amine with at
benzene diazonium chloride is formed

Answer 16

nitrous acid (NaNO2 + HCl) , ~5°C,

Question 17

SOLUBILITY TEST results

phenol in 5% NaOH

Answer 17

soluble; clear dark brown to black solution

Question 18

Identify solubility
of phenols

Answer 18

SOLUBILITY TEST

Question 19

 principle: phenols react with
dilute aqueous sodium hydroxide
to form (more soluble with water compared to
phenol due to its phenyl ring)

Answer 19

sodium phenoxide

Question 20

Solubility Test

phenols react with
to form Na phenoxide (more soluble with water compared to
phenol due to its phenyl ring)

Answer 20

dilute aqueous sodium hydroxide

Question 21

REACTION WITH FERRIC CHLORIDE results

1% phenol

Answer 21

purple soln

Question 22

REACTION WITH FERRIC CHLORIDE results

1% cathecol

Answer 22

clear colorless solution

Question 23

REACTION WITH FERRIC CHLORIDE results

1% thymol

Answer 23

Clear pale green soln

Question 24

REACTION WITH FERRIC CHLORIDE results

1% α-naphthol

Answer 24

Dark red sol

Question 25

function of test: can detect the presence of
phenolic compounds

Answer 25

REACTION WITH FERRIC CHLORIDE

Question 26

 reagent: ferric chloride

Answer 26

REACTION WITH FERRIC CHLORIDE

Question 27

Rxn with Ferric Chloride

 principle: formation of that
absorbs visible light to give an excited state
in which electrons are delocalized over both
the iron atom and the conjugated organic
system

Answer 27

ferric phenoxide

Question 28

BROMINE WATER TEST results

1% phenol

Answer 28

clear colorless solution with white precipitate

Question 29

BROMINE WATER TEST results

salicylic acid

Answer 29

clear colorless solution with white precipitate

Question 30

function of test: can be used to identify phenolics (however, other
compounds may also yield positive results)

Answer 30

BROMINE WATER TEST

Question 31

 reagent: bromine water

Answer 31

BROMINE WATER TEST

Question 32

positive result: bromine water test

Answer 32

clear colorless solution with white precipitate

Question 33

Bromine Water Test

 principle: bromination of phenol results to product which
appears as white precipitate while

the results to decolorization of the solution with an odor of an antiseptic

Answer 33

2,4,6-tribromophenol

side product of hydrobromic acid

Question 34

FORMATION OF PHENOLPHTHALEIN results

5% HCl

Answer 34

clear colorless solution

Question 35

FORMATION OF PHENOLPHTHALEIN results

5% NaOH

Answer 35

pink soln

Question 36

can also be used as precursor in the synthesis of several organic
compounds

 one of which is an, used in acid-base titration

Answer 36

phenol

organic indicator phenolphthalein

Question 37

Formation with phenolphthalein

phenol reacts with - under an
acid catalyst using an electrophilic aromatic
substitution reaction

 the resulting solution can be further tested for its
indicator property:

in acidic solutions
in basic solutions

Answer 37

phthalic anhydride

colorless

pink to magenta

Question 38

phenol reacts with phthalic anhydride under an
acid catalyst using an

Answer 38

electrophilic aromatic
substitution reaction

Question 39

MILLON’S TEST results

1% phenol

Answer 39

clear golden brown solution

Question 40

MILLON’S TEST results

5% albumin

Answer 40

clear yellowish solution with red precipitate

Question 41

determine the presence of
phenolic compounds in amino acids

Answer 41

MILLON’S TEST

Question 42

 reagent: Millon’s reagent

Answer 42

(mercurous nitrate HgNO3 and mercuric nitrate Hg(NO3)2 in nitric acid
HNO3)

Question 43

positive result: millons test

Answer 43

red precipitate

Question 44

(is the only amino acid with phenol in its
structure)

Answer 44

tyrosine

Question 45

 principle: react with Millon’s reagent to form red colored complexes

Answer 45

amino acids and proteins with phenol radicals

Question 46

 principle: amino acids and proteins with phenol radicals react with Millon’s reagent to form

Answer 46

red colored complexes

Question 47

 positive result: rxn with ferric chloride

Answer 47

colored complexes