MIND MAP OF CHAPTER 8.0 HYDROXY COMPOUNDS

MIND MAP
HYDOXY
COMPOUNDS

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PHYSICAL PROPERTIES OF ALCOHOL
(BOILING POINT: ALCOHOL, HALOALKANE & ALKANE)

Comparision Alkanes Haloalkanes Alcohol
Polarity Non polar Polar Polar

London forces London forces, dipole-
Type of IMF available London forces and dipole- dipole forces and
Hydrogen bond
dipole forces
Hydrogen bond
Strongest IMF London forces Dipole-dipole
available forces Most

Energy/Heat needed Little More Highest
to overcome the IMF

Boiling point Lowest High

Alkanes < Haloalkanes < Alcohol

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PHYSICAL PROPERTIES OF ALCOHOL

(BOILING POINT AMONG ALCOHOL)

DIFFERENT SIZE BUT SAME NO. OF OH GROUP SAME SIZE BUT DIFFERENT NO. OF OH GROUP

Alcohol Small Alcohol Large alcohol Example 1,3-butanediol Butanol

Polarity Polar molecules Polarity Polar molecule
Hence, both have dipole-dipole forces Hence, both have dipole-dipole forces
No. of OH group No. of OH group
Same. Hence, both have same magnitude of Type of IMF available 21
Hydrogen bond
Size
Type of IMF London forces, Dipole-dipole forces and Hydrogen London forces. Dipole-dipole forces and
available Strength of IMF Hydrogen bond
Size bond Energy/heat needed
to overcome the IMF
Small Large Same. Hence, both have same magnitude of
Boiling point London forces
Strength of IMF Weak Strong

Energy/heat Less More Strong Weak
needed to Low High
overcome the IMF More Less
Boiling point
High Low

STRAIGHT VS BRANCHED CHAIN

1O ROH 2O ROH 3O ROH

Polarity Polar

No. of OH group Same

Type of IMF available London forces, Dipole-dipole forces and Hydrogen bond

Surface area in contact Biggest Big Small

Strength of IMF Strong Weak Weakest

Energy/heat needed to overcome the IMF Most More Less

Boiling point High Low Lowest
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PHYSICAL PROPERTIES OF ALCOHOL
(SOLUBILITY OF ALCOHOL)

SAME NO OF CARBON

No of C C1 – C4 C5 ≥

Ability to form Hydrogen bond Yes Large
BUT Low

Hydrophobic area Small
Water solubility High

DIFFERENT NO OF CARBON

Example 1,3-butanediol Butanol

No of OH group 2 1

Hydrogen bond formed More Less

Water solubility High Low

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PREPARATION AND CHEMICAL PROPERTIES OF HYDROXY COMPOUNDS

MgCl (Hydration of alkene)
Markovnikov’s rule:
(Dehydration of alcohol) CH2CH3 In the addition of HX to unsymmetrically
Saytzeff rule: alkene, the hydrogen atom added to the
In an elimination, alkene with H carbon double bond having greater no of
greater no alkyl group at C=C is the hydrogen.
most stable and as major product. CH3CH=CHCH3 i) CH3C=O CH2=CHCH2CH3
ii) H3O+ Cl
CH3CHCH2CH3
O-Na+ Conc H2SO4 H2O/ H+ H2O/ H+
CH3CHCH2CH3 O
Metal Na Na+O-CHCH2CH3 + CHI3
reaction OH
Iodoform test: I2/ NaOH
Other SOCl2 CH3CHCH2CH3 I2 / NaOH To detect methyl carbinol
reagents: Yellow precipitate formed
PCl5 or Cl O H+
HX or CH3CHCH2CH3 CH3C-OH
PX3 KMnO4 / H+ +

Conc HCl / ZnCl 2

O O Cl
OCCH3 CH3CCH2CH3 CH3CHCH2CH3
CH3CHCH2CH3

Esterification

Oxidation: KMnO4 @ K2Cr2O7 @ Na2Cr2O7 , H+ / ∆ Lucas Test: Conc HCl/ ZnCl2

10 alcohol: Carboxylic acid 10 alcohol: No cloudiness formed within 10 minutes
20 alcohol: Ketone 2o alcohol: Cloudiness formed within 5-10 minutes
30 alcohol: No reaction 3o alcohol: Cloudiness solution immediately formed

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CHEMICAL TEST OF ALCOHOL

Class of Lucas Test Observation
alcohol
Function : To distinguish 1°, 2°, and 3° alcohol
Primary
(1°) Reaction

Secondary CH2 OH ZnCl2 / conc HCl No observable change within 10 minutes.
(2°) No reaction

Tertiary OH ZnCl2 / conc HCl Cl Solution turns cloudy within 5 minutes
(3°) CH3 Turns cloudy immediately
CH3OH ZnCl2 / conc HCl
Cl

Iodoform Test

Function : To identify methyl carbinol group
Methyl carbinol cleavage to give carboxylic acid and iodoform.

Reaction Observation

methyl OH H I2, H+ O Yellow precipitate formed
carbinol H3C C OH-
HO C H + CHI3
H iodoform

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ACIDITY OF ALCOHOL

Strength of acidity : phenol > water > alcohol

Stability : phenoxide ion > hydroxide ion > alkoxide ion

phenoxide ion hydroxide ion alkoxide ion

O- OH- RO-

• Phenoxide ion is more stable than OH- • No –R group • -R group as electron donating
and RO- ions due to the resonance • The hydroxide ion is more stable group(EDG) destabilized the
stabilization effect. alkoxide ion.
than the alkoxide ion. Less acidic than H2O.
• The electrons in phenoxide ion are
delocalized into the benzene ring. More acidic than ROH. O

More acidic than H2O. O O -

O- -

-

Due to this stability, more phenoxide and hydrogen ions are formed, making it a stronger acid than alcohol and water. Phenols react
with a base such as NaOH to give sodium salts and water, whereas alcohols do not.

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REACTION WITH SODIUM METAL

OH O- Na+

+ Na

CHEMICAL TEST OF PHENOL

Reaction with NaoH Phenol Test

Function : To differentiate aliphatic alcohol and phenol Function : To differentiate between phenol and others.

OH O- Na+ OH OH

+ NaOH + FeCl3 FeCl3

Observation : 1 layer solution formed Observation : Turns the yellow colour on aqueous FeCl3
to purple complex
OH

+ NaOH insoluble in water Using aqueous Bromine

Function : To differentiate between phenol and others.

OH OH

Observation : 2 layer solution formed + 3Br2 / H2O Br Br

• Aliphatic alcohol does not react with NaOH + 3HBr

• lcohol is a weaker acid compared to phenol (phenoxide Br
ion is more stable compared to alkoxide ion)
Obsevation : White precipitate formed
• NaOH is often used as a chemical test to differentiate
alcohol with phenol.

Prepared by: NFAG, KMPh

Prepared by: NFAG, KMPh