Organic bases are different from general bases here is all details about organic bases . Their strength and factors affecting their strength. We also discuss its applications. We will also upload organic acids and their strength very soon.

1. PRESENTATION OF CHEMISTRY
TOPIC: ORGANIC ACIDS AND BASES
PREPARED BY: AZIZ KHAN
PRESENTERS: AZIZ KHAN
SUBHAN ULLAH
HAQ NAWAZ
UMER FAROOQ
ZEENAB
AIMAN

2. ORGANIC BASES
WHAT ARE ORGANIC BASES?
Organic bases are organic compounds which acts as a
base. Organic bases are usually but not always proton
acceptors amines and hydrogen
containing heterocyclic compounds
are organic bases.
EXAMPLE: Pyridine , methyl amine etc

3. PYRIDINE AND METHYL AMINE
PYRIDINE METHYL AMINE

4. Some organic bases are hydroxide
donors
TETRAMETHYL AMONIUM HYDROXIDE

5. PROPERTIES OF ORGANIC BASES
1. Usually proton acceptor.
CH3NH2+H2O CH3NH3 + OH-
2. Some are Hydroxide donors.
Example:
Tetra methyl ammonium
hydroxide (explained above)
3. They are generally weak bases.

6. Other properties are similar to that of
inorganic bases.
3. They have a ph of more than 7.
4. They have a soapy feel.
5. They have a bitter taste.
6. They are corrosive to human
tissue.
7. They react with acid to form
salt and water.

7. FACTORS AFFECTING STRENGTH OF
ORGANIC ACIDS
1. STABILITY OF ANION: Acidity is directly
proportional to stability of anion. When the anion
will be more stable it will not react in the
backward direction and hence
more H+ ions will produce.
For example : which one is more acidic.
a. HCOOH b. CH3COOH
The anion of HCOOH is more stable than CH3COOH
because CH3COOH have positive inductive effect.

8. EXPLANATION
HCOOH HCOO- + H+
ANION: HCOO- Stable because no inductive
effect.
CH3COOH CH3COO- + H+
anion is not stable due to
positive inductive effect.
+ INDUCTIVE
EFFECT

9. ELECTRONEGATIVITY
Electronegativity is directly proportional to acidic
strength. Increasing the number
of electronegative atoms or groups on atom
decreases the electron density in the acidic bond,
making the
loss of the proton easier.
For example: in H X the X attract electron
pair towards itself and hence decreasing the
strength of HX bond and hence it will easily
donate H+. So it is a strong acid.

10. ACIDITY TREND

11. HYBRIDIZATION
As we know that SP3 is less electronegative than
SP2 and SP2 is less electronegative than SP
so acidity order will be.
SP>SP2>SP3
So the acidity order of the following
Compound will be.
CH3CH2COOH<CH2 CHCOOH<CH C COOH
SP3 SP2 SP

12. INDUCTIVE EFFECT
Positive inductive effect is inversely
proportional to acidity while negative
inductive effect is directly proportional to
acidic strength . Because in + inductive effect
one atom destabilize an anion
by giving it an electron. While in – inductive
effect an atom stabilize anion by withdrawing
electron from it.

13. EXPLANATION
a. CH3 CH3COOH b. CH2CH3COOH
c. FCH3COOH
The acidity order will be
a<b<c
c is more acidic because of negative inductive
effect b is less acidic because of single
positive inductive effect and a is very less
acidic because of double positive inductive
effect.
CH3

14. RESONANCE
In resonance the formal charge and the unpaired
electron is shared by more than two nuclei hence
stabilizing the compound.
For example:
a. ROH b. COOH
b is more acidic than a because of resonance.
ROH H+ + R O-
RCOOH

15. AROMATICITY
A compound which become aromatic after
donating proton will be more acidic.
FOR EXAMPLE:
NaNH2
_

16. FACTORS AFFECTING STRENGTH OF
ORGANIC BASES
AVAILABILITY OF LONE PAIR: Most of the
organic bases are Lewis bases and we all know
that Lewis bases are those bases which donate
lone pair of electron.
N
H
H
R
H+
RNH3

17. CHARGE
One definition of a base is to accept proton .
More negative charge means more probability
to accept proton.
EXAMPLE:
a. A+ b. B c. C- d. D-2
NOT
BASIC
NEUTRAL BASIC MORE
BASIC

18. ELECTRONEGATIVITY
When an atom have greater electronegativity it
means that the atom is greedier for electrons.
It is less willing to share its electron pair. So it is
less basic. Electronegativity is inversely
proportional to basicity.
EXAMPLE:
a. CH3 N CH3 b. CH3CH2
CH3
F
N is less
electronegative and
hence more basic
F is more
electronegative and
hence less basic.

19. HYBRIDIZATION
The order of basicity in hybridization will be
SP3 > SP2 > SP
In SP3 hybridization the hybridized orbital is
form from three orbitals and hence have
greater size and less electronegativity and are
more basic while SP2 and SP have relatively
smaller size and hence greater
electronegativity and they are less basic.

20. EXPLANATION
a. b.
N N
H
It is less basic
because of SP2
hybridization(high
electronegativity)
It is more basic
because of SP3
hybridization(low
electronegativity)

21. ATOMIC SIZE
Size is inversely proportional to basicity. Atoms
with smaller atomic size will have greater
electron density increasing basicity while
atoms with larger atomic size will have less
electron density reducing basicity.
EXAMPLE:
a. CH3Br b. CH3CH2CO2
-
It is less basic due to
the greater size of Br
It is more basic due to
the smaller size of O

22. EXPLANATION
Br O
Br have large size
and small electron
density and is
difficult for acceptor
to attack hence less
basic.
O have small size and
greater electron
density and it is very
easy for acceptor to
attack and hence more
basic.

23. INDUCTIVE EFFECT
When atom in a molecule give or take electron
from atom donating electron or proton it is
known as inductive effect. It has two types.
POSITIVE INDUCTIVE EFFECT:
When an atom give electron to a
donating atom.
NEGATIVE INDUCTIVE EFFECT:
When an atom withdraw an electron from
donating atom.

24. EXPLANATION
Positive inductive effect is directly proportional
to basicity while negative inductive effect is
inversely proportional to basicity.
EXAMPLE:
a. CH3 N H b. NO2 N CH3
H CH3It is basic due
to positive
inductive effect
It is less basic due
to negative
inductive effect

25. ORDER FOR BASICITY OF AMINES
PRIMARY AMINES < SECONDARY AMINES >
TERTIARY AMINES
Primary amines have single + inductive effect
That is why it is less basic while secondary
carbon have double + inductive effect that is
why it is more basic while tertiary have triple
inductive effect but it is completely cover by
groups which allow very little contact of donor
and acceptor and hence are less acidic.

26. TRAGIC CHANGE IN AMINES BASICITY
a. CH3 NH2 b. CH3 NH CH3
c. CH3 N CH3
CH3
Single positive
inductive effect
less basic.
Double positive
inductive effect more
basic.
Less contact of donor
and acceptor less basic.

27. RESONANCE
Resonance is inversely proportional to basicity
because resonance decrease electron density
delocalizing the charge as will as the electrons
hence decreasing the basicity.
a. CH3 NH CH3
b.
ELECTRON
DENSITY
NH2
ELECTRON
DENSITY

28. RESONANCE IN BENZENE

29. EXPLANATION
In resonance the electrons are busy in
delocalization and are not available for
donation hence decreasing basicity.

30. NO EFFECT OF RESONANCE
Some time resonance have no effect on
basicity.
EXAMPLE:
C O-
H
H
RESONANCE

31. BUT IN THIS CASE IT WILL EFFECT
CH3CH2CO2
-
C C C
H
H
H
H H
O&-
O&-
RESONANCE

32. APPLICATION OF ORGANIC BASES
1. Pyridine is used as a versatile solvent.
Deuterated pyridine (pyridine-d5) is a common
solvent for HNMR spectroscopy.
2. pyridine- borane C5H5NBH3
(M.P 1O-11C) is a mild reducing
agent with improved stability
compared to sodium boro hydride (NaBH4) in
protic solvents and approved solubility in
aprotic organic solvent.

33. 3. Pyridine is used as a denaturant for anti
freeze mixtures.
4. Pyridine is sometimes used as a ligand in
coordination chemistry.
5. Imidazole has been used extensively as a
corrosion inhibitor on a certain metals like
copper.
6. Imidazole can also be found
in various compounds that are
used for photography and electronics.
7. The thermo stable polybenzimidazole contain
imidazole fused to a benzene ring and act as a
fire retardant.

34. 8. Methyl amines is used to make
intermediates for wide range of agriculture
chemicals including herbicides, fungicides,
insecticides, biocides and miticides.
9. Alkynealkanolamines have a large use in the
treatment of natural gas and oil.
10. P-methylaminophenol sulfate
Used as a photographic developer.
11. Methyl amines are also used
As an animal nutrients , catalyst , electronics
and explosives.
12. Benzemedazoles are often bioactive.

35. Many anthelmintic drugs (albandazol ,
mebendazole , triclabendazole , belongs to
the benzimedazole class of compound.
13. Benzimedazole also binds to the
spindle microtubules and blocks nuclear
division.
14. Benzimedazole is also used
in several dyes.

36. BY
AZIZ KHAN