Summary - Unit 12 - Acid-base Equilibria

ACID-BASE EQUILIBRIA
BRONSTED-LOWERY THEORY


ACIDS >
-
proton donors

BASES- - proton acceptors

PROTIC/BASIC
-
H+ ions interchangeable

CONJUGATE PAIRING
form * hydroxonium ions in water
mono profic Inol acid 1 mol h +
↳ make the solution acidic CONJUGATE ACID
-




dipetic 1 mol acid 2 mol nt
Ht
eg : HA HOT Conjugate
prozon (UH)
gaining U + gained a
tripetic 1 mol acid f 3 mo At
~ pair
-
-
- CONJUGATE
lost a proton
BASE
(Ht)
HA a
WEAU



STRONG ACID
ACID -




-
partially


fully
dissociates



dissociates
in water to




water to
produce



produce
H + ions



H + ions
Tequilibrium

[equilibrium well
me
well over to



over to the
left]


right]
[AcidugtHHoa
& Closing
in


conjugate pair
gamingt
WEAK ACID WEAK BASE
acid conjugate
W HONN
CH3 COOM = H+ CH , 100-

- I
e. e
.
g g
.
.

+

ethanoic acid favoured



ChycOOMad + 1201 U0tlag CuC00
STRONG BASE +
STRONG ACID strongly smongly as
favoured
favoured
C- - NaOH
--
+
monoprotic HCl F-H + + e .

g H- + Na
e .

.
g
acid
hydrochloric
e K On conjugate base
? .


.
g U2504
.

.
g
diprotic
e .
g
Monoprotic UNOz
.




PU OF STRONG ACID PH OF STRONG BASES MEASURI
↳ [n + ]
conc
↳
=



Con]
.




conc =
fully dissociates
↳ pH
.




If diprotic . H2SO4 fully
: dissociates
e .

g
-log[H ]
+
pH =

[n ] 10
-
pu
MUST
+
be calibra
kw
dn'
[H + J [OH-]
=
- to define 0 1S mol
this C of NaOH at 298K
.

↓
use
g
. . .


= >
-




ph e . 2Snolan's
g U2SO4 the ionic product of
pu 2 ] 10-
.


+
-10g[6 7x10-1]
> =
water -1
[H ]
-




[H ]
1x10
-




10 - 10g 10 25 x 2) pu
+
15
+ pu x 0
= =
.




=
.




↳ product
.

=
pu
#O
= of molar conc
13 18
3(n +] 10
- =

30
= kw/(On -
0
[H ]
=
.




of Ht and Oft at a
*




= .




[ pu always
[ pu always to (n +] Specified temperature
6 7x10
+4
=
[H ]
+ 2 dp
to

2 dp
.




↓
UNDERSTA
-log [H ]
+
pH =



(n + ] [OH -]




pLwETOgl
[1x10-3] [1x10
-




1]
14
L STRONG AC
pH OF WEAK ACIDS kw 1 10 molan-b
-


= x

↳ ionic product of water dan's
1 UC1
4 conc = [u ] +
↳ changes if of changes
[n ] 180
.




+ = :




pure water : (H ]+ = [On -] >
-
Uw = [n ]
+
2
↳ puw is used to display
No values on a smaller scale




Ka
= A
Isolate

(2) .. dissociation of
so al [h +]
a
dison


acid + than that of
must come from me acid
water
WEAL AC


=
1 dan's CHOO

Ka
-log[H ]
e
.
g 0 03 molan's Chycoon 298K
. OR pH 3 14 ncoon 298h
+
pH
at e
g at
.
.




[U ]
. . .


"
Ua = 1 76 x 10-s mol
. dn'3
Ha = 1 77
.
x 10 ↑Mol
-

an
3 = +
= 10
14
↓ ① 1 ma
① CH ) 10-3
.

+
ny
=
Ka
=




NaCHA]
↑
7 2 10
-




x

(H ]
= .


+
=
②
(H) NT16x10-s(X003

,
:




↓
log[n ]
kw [H + J [OH-]
+ - Y
ph =
-
= 7 . 3 x 10
=
③ pH =
- 10g[7 .
3 x10 - 4)
=
3 . 14
= 2 .
97 x 10-3 mol an
3




ACID DILU
pKw =
-log (kw) ↳
pla ALTERNATIVE MEASUREMENT OF ACID STRENGTH

DILUTING



pKa-log(na) -

Pha
e .
g




①
. 0 025 mol dn's
.




pua =
4 TS
.




18-4
Chycoon



T
at 2981




ka
= A d

10
.




Ka
na
=
=
=
1 78
.
x 10-s

n
↑ pha =
stronger
acid
the
e
②a 00s
DILUTING
6 67x10 4


pka -log(na)
-




=
= .




③ ph - 10g (6 67x10 "]
din
-




=
.




3 .
18 X




pH =

pha +
log()
TITRATIONS AND TITRATION
CURVES
n
now




on 1
&
a

Digia
g
volume of acid added




PM heter
P
mus i

(methyl orange] (methylorange] (phenolphthalein) 10 shapchange
-




iL
14




=

·
O O
of base volume of base added
volume of base added volume of base added volume added


U
p1 = pua pu 4 -p19
pu1 >
pU13 pu 4
-
p413
-




excess excess
excess
I
excess excess
I ↳excesabuse i ↳
strong acid
↳ strong base
strong acid said & ↳ sees has weanacia wear base




strong base pu9t
"v
acid + SB
weal O
acid + strong base pu7
strong
=