Chapter 3: Acids and Bases
Acidic site
Acidic site COCHE
↳
OH -
H2N CH3
X
O
Basic site Alanine
Aspirin
O
O
Acidic site
HO L
OH
-
Acidic sites
·
& NH2
↑
HO Basic site
-
Dopa
*
Strong acids
· Acidic type of organic molecule = Carboxylic acid/Alcohols Nitric
As Electro pair acceptors Sulfuric
B. Electron pair donors HI
C) Ht acceptors HBr
+
,
D H donors He
E, Both Cand D are correct Perchloric
⑰ Both A and D are correct
* The Lewis acid-base definition = An acid is an electron pair acceptors which mean with the H+ donors
· Base type of organic Molecule = Amine
General
I
Bronsted -
Lowry Acid-Base reaction :
donate proton
Bronsted-Lowry definition :
-
H -
A + Ba >: A + B -
H
[
Acid - H+ donor
Acid
(HCl, H2SO4, HNO3, CH3CO2H) Base Conjugate Conjugate
Base Acid.
Base - H+ acceptor
(OH-, NH3, CH3NH2, CH3O-,..)
,# .
Using curved ar rows
· Curved a r rows a re used to show e movement
&
in all types of organic reactions
H*
+
+ B : ) A + B H
=
:
-
* The tail of the a r row always starts e
at a n
pair
* Net charge is the same on both sides of the equation .
-
·
jo
Unlike a r rows used for resonance structures,
these Do show
bonding changes .
#. Acid Strength de dang
↓
The the more H+
stronger the acid , readily it donates
--
H -
A + % [
>
A : + H - -
H
E
S
i
O
H H
For the
strong acids ,
the right side is favored
+
[A-][HzO ] pKa -Log ka
[a
=
=
[HA]
Smaller pKa —> stronger acid >
- Some of the strongest acid has
very
- 7
Acidity constant
values of 5 - 50 are common for low value of pka = X10
larger Kaz Stronger acid
organic compounds
Which of those has the base ?
following strongest conjugate
very
A , CH3CO2H (pKa =
4 .
8) ↳ strong
acid
>
-
B, HC (pka =
-
7) CH20)
lethanol) Almost
a NHs (pka = 38) largest pKaz weakest acid
Cacetylene)
(Hydrogen)
⑪ CHzCHzCHs (pKa = 50) #
↳ weaker acid ,
the
stronger Base
>
-
(NH3)
C
(Alkane]
E
,
H20 (pKa =
15 .
7) conjugate base .
Propane
, has the weakest base ?
Which of the following conjugate
A , H2 (pka = 35)
B
, CH4 (pKa = 50)
C) NH3 (pKa = 38)
D HF(pKa =
3 .
2) smallest plat stronger acid) weakest conjugate base
⑰ HBr(pka = -g)
IV . Acid-Base Reactions
How do we know which side of the equation is favored at equilibrium ?
- W
H -
A t B : -
: A + B -
H
• Formation of the weaker acid is
favored
-
Acid Base Conjugate Conjugate
• If the pKa of the acid is lower than
Base acid .
the pKa of the conjugate acid, the
products are favored
O
O
NH2 NH3
o
t
OH +
-
PKa = 4 2 .
pKa =
4 6
.
↓ The equilibrium favors the
the smaller pia which A the
, starting materials
mean the stronger acid which ⑪ The products
push the conjugate acid
away
=> the product will be favored
methylamine
↓
CH3NH2 +
OH CHsNH + H20 The conjugate acid has the smaller pla
-
L
PKa =
40 pKa = 15 7
.
which mean it can push the starting
material away , that mean it's a
the equilibrium favors the stronger acid
⑰ The starting materials
By Products .
Acidic site
Acidic site COCHE
↳
OH -
H2N CH3
X
O
Basic site Alanine
Aspirin
O
O
Acidic site
HO L
OH
-
Acidic sites
·
& NH2
↑
HO Basic site
-
Dopa
*
Strong acids
· Acidic type of organic molecule = Carboxylic acid/Alcohols Nitric
As Electro pair acceptors Sulfuric
B. Electron pair donors HI
C) Ht acceptors HBr
+
,
D H donors He
E, Both Cand D are correct Perchloric
⑰ Both A and D are correct
* The Lewis acid-base definition = An acid is an electron pair acceptors which mean with the H+ donors
· Base type of organic Molecule = Amine
General
I
Bronsted -
Lowry Acid-Base reaction :
donate proton
Bronsted-Lowry definition :
-
H -
A + Ba >: A + B -
H
[
Acid - H+ donor
Acid
(HCl, H2SO4, HNO3, CH3CO2H) Base Conjugate Conjugate
Base Acid.
Base - H+ acceptor
(OH-, NH3, CH3NH2, CH3O-,..)
,# .
Using curved ar rows
· Curved a r rows a re used to show e movement
&
in all types of organic reactions
H*
+
+ B : ) A + B H
=
:
-
* The tail of the a r row always starts e
at a n
pair
* Net charge is the same on both sides of the equation .
-
·
jo
Unlike a r rows used for resonance structures,
these Do show
bonding changes .
#. Acid Strength de dang
↓
The the more H+
stronger the acid , readily it donates
--
H -
A + % [
>
A : + H - -
H
E
S
i
O
H H
For the
strong acids ,
the right side is favored
+
[A-][HzO ] pKa -Log ka
[a
=
=
[HA]
Smaller pKa —> stronger acid >
- Some of the strongest acid has
very
- 7
Acidity constant
values of 5 - 50 are common for low value of pka = X10
larger Kaz Stronger acid
organic compounds
Which of those has the base ?
following strongest conjugate
very
A , CH3CO2H (pKa =
4 .
8) ↳ strong
acid
>
-
B, HC (pka =
-
7) CH20)
lethanol) Almost
a NHs (pka = 38) largest pKaz weakest acid
Cacetylene)
(Hydrogen)
⑪ CHzCHzCHs (pKa = 50) #
↳ weaker acid ,
the
stronger Base
>
-
(NH3)
C
(Alkane]
E
,
H20 (pKa =
15 .
7) conjugate base .
Propane
, has the weakest base ?
Which of the following conjugate
A , H2 (pka = 35)
B
, CH4 (pKa = 50)
C) NH3 (pKa = 38)
D HF(pKa =
3 .
2) smallest plat stronger acid) weakest conjugate base
⑰ HBr(pka = -g)
IV . Acid-Base Reactions
How do we know which side of the equation is favored at equilibrium ?
- W
H -
A t B : -
: A + B -
H
• Formation of the weaker acid is
favored
-
Acid Base Conjugate Conjugate
• If the pKa of the acid is lower than
Base acid .
the pKa of the conjugate acid, the
products are favored
O
O
NH2 NH3
o
t
OH +
-
PKa = 4 2 .
pKa =
4 6
.
↓ The equilibrium favors the
the smaller pia which A the
, starting materials
mean the stronger acid which ⑪ The products
push the conjugate acid
away
=> the product will be favored
methylamine
↓
CH3NH2 +
OH CHsNH + H20 The conjugate acid has the smaller pla
-
L
PKa =
40 pKa = 15 7
.
which mean it can push the starting
material away , that mean it's a
the equilibrium favors the stronger acid
⑰ The starting materials
By Products .
