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Ion equilibrium Ion equilibrium

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Page 1: ˘ˇ - Chem ku-kpschem.flas.kps.ku.ac.th/SLIDE/SLIDE-53-TEACHER-ION... · 1. strong electrolyte ˘ˇ˘ˆ˙˝ ˛˚˜ !"#$%&'(˜ )*˚ HCl HNO HClO NaOH KOH NHCl NaCl ˘ˇ ˆ ˙ ˝˛˙

����������Ion equilibriumIon equilibrium

����������

��� ��� ������������� �����

��������������� ����� �����������������

Page 2: ˘ˇ - Chem ku-kpschem.flas.kps.ku.ac.th/SLIDE/SLIDE-53-TEACHER-ION... · 1. strong electrolyte ˘ˇ˘ˆ˙˝ ˛˚˜ !"#$%&'(˜ )*˚ HCl HNO HClO NaOH KOH NHCl NaCl ˘ˇ ˆ ˙ ˝˛˙

1. strong electrolyte ������������� ��!"#$%&��'(� )*��

HCl HNO HClO NaOH KOH NH Cl NaCl

������������� ����

��� �������� �������� ������������������� ���������������� ���������� !��"�

2

HCl HNO3 HClO4 NaOH KOH NH4Cl NaCl

2. weak electrolyte �������������&��'(� )*��

HNO2 HClO2 H2SO3 CH3COOH NH4OH BaSO4

3. Non electrolyte ��#678���������&��'(� ��9����(��::;� )*�� ��"<=� >"<=#�

Page 3: ˘ˇ - Chem ku-kpschem.flas.kps.ku.ac.th/SLIDE/SLIDE-53-TEACHER-ION... · 1. strong electrolyte ˘ˇ˘ˆ˙˝ ˛˚˜ !"#$%&'(˜ )*˚ HCl HNO HClO NaOH KOH NHCl NaCl ˘ˇ ˆ ˙ ˝˛˙

�#�-)!� (Acid- Base)

1. ArrheniusG �#� =H� ��#678�9����'(�����&I� H+

��������������� �-���

ClHHCl−+

+→

3

G )!� =H� ��#678�9����'(�����&I� OH-

=����# KL'���!��#������&I������

ClHHCl aqaqaq+→

)()()(

OHKKOH aqaqaq−+ +→ )()()(

Page 4: ˘ˇ - Chem ku-kpschem.flas.kps.ku.ac.th/SLIDE/SLIDE-53-TEACHER-ION... · 1. strong electrolyte ˘ˇ˘ˆ˙˝ ˛˚˜ !"#$%&'(˜ )*˚ HCl HNO HClO NaOH KOH NHCl NaCl ˘ˇ ˆ ˙ ˝˛˙

#��$����"

♦♦♦♦ ��#��'���� �9����'(����)6����'� ��9��#��'�����7 H+

I#H� OH- &�<�)���� M9�������#N!��������)OP��#�-)!� )*��

NH3 OH-

H2O

4

NH3 OH

NH3 + H

2O NH

4+ + OH-

NH4Cl NH

4+ + Cl-

NH4+ + H

2O NH

3 + H

3O+

Page 5: ˘ˇ - Chem ku-kpschem.flas.kps.ku.ac.th/SLIDE/SLIDE-53-TEACHER-ION... · 1. strong electrolyte ˘ˇ˘ˆ˙˝ ˛˚˜ !"#$%&'(˜ )*˚ HCl HNO HClO NaOH KOH NHCl NaCl ˘ˇ ˆ ˙ ˝˛˙

2. Bronsted-Lowry

�#� =H� ��#678&I� H+ )!� =H� ��#678#�! H+

="��#�-)!� (conjugate acid-base pairs)

5

HA �����'(��"#�) A- ��� A- �����'(�+�#�) HABH+ �����'(��"#�) B ��� B �����'(�+�#�) BH+

Page 6: ˘ˇ - Chem ku-kpschem.flas.kps.ku.ac.th/SLIDE/SLIDE-53-TEACHER-ION... · 1. strong electrolyte ˘ˇ˘ˆ˙˝ ˛˚˜ !"#$%&'(˜ )*˚ HCl HNO HClO NaOH KOH NHCl NaCl ˘ˇ ˆ ˙ ˝˛˙

HF + H2O H3O+ + F-

�#� 1 )!� 1�#� 2)!� 2

NH4+ + H2O NH3 + H3O

+

="��#�-)!� (conjugate acid-base pairs)

6

HNO2 + H2O H3O+ + NO2

-

NH3 + H2O NH4+ + OH-

Page 7: ˘ˇ - Chem ku-kpschem.flas.kps.ku.ac.th/SLIDE/SLIDE-53-TEACHER-ION... · 1. strong electrolyte ˘ˇ˘ˆ˙˝ ˛˚˜ !"#$%&'(˜ )*˚ HCl HNO HClO NaOH KOH NHCl NaCl ˘ˇ ˆ ˙ ˝˛˙

#����)���

•••• �'(�)OP����6�' �#���9)!� (amphoteric substance) ������� amphoteric )*�� NH3 HSO4

- HCO3-

•••• �#���9)!���M��"�&�#"O<�)����I#H������

7

•••• �#���� �7 ="�)!�)OP�)!����� )*�� HClO4 �#���� : ClO4

- )!����� )!���� �7 ="��#�)OP��#����� )*�� NH2

- )!���� : CH3NH2 �#�����

•••• �#���9)!���M��"�&�#"O<�)����I#H������

Page 8: ˘ˇ - Chem ku-kpschem.flas.kps.ku.ac.th/SLIDE/SLIDE-53-TEACHER-ION... · 1. strong electrolyte ˘ˇ˘ˆ˙˝ ˛˚˜ !"#$%&'(˜ )*˚ HCl HNO HClO NaOH KOH NHCl NaCl ˘ˇ ˆ ˙ ˝˛˙

•••• �#� =H� ��#678����#N#�!="��Y)�Z��#��

•••• )!� =H� ��#678����#N&I�="��Y)�Z��#��

3. Lewis acid

�+���"OHHOHH :: →+ −+

8

8

��#678)OP��#���� Lewis (Lewis acid)1. �=������ : Na+ Be2+ Mg2+ Ag+

2. <�)����678�9������ �7�Y)�Z��#�����=#!�O� BF3

3. �7]��^9="���!�9���678�7=�� EN ��� ��� SO3

�+���"

Page 9: ˘ˇ - Chem ku-kpschem.flas.kps.ku.ac.th/SLIDE/SLIDE-53-TEACHER-ION... · 1. strong electrolyte ˘ˇ˘ˆ˙˝ ˛˚˜ !"#$%&'(˜ )*˚ HCl HNO HClO NaOH KOH NHCl NaCl ˘ˇ ˆ ˙ ˝˛˙

1. �������� OH-

2. �9������ 678�7�Y)�Z��#��="�<��)�78��

���������+���� Lewis (Lewis base)

9

H2O NH3

H2C=CH2 + 2HBr H3C-CH3 + Br2

3. ��# hydrocarbon (CH) 678�7]��^9="�

Page 10: ˘ˇ - Chem ku-kpschem.flas.kps.ku.ac.th/SLIDE/SLIDE-53-TEACHER-ION... · 1. strong electrolyte ˘ˇ˘ˆ˙˝ ˛˚˜ !"#$%&'(˜ )*˚ HCl HNO HClO NaOH KOH NHCl NaCl ˘ˇ ˆ ˙ ˝˛˙

Lewis acid - base

10

10

Page 11: ˘ˇ - Chem ku-kpschem.flas.kps.ku.ac.th/SLIDE/SLIDE-53-TEACHER-ION... · 1. strong electrolyte ˘ˇ˘ˆ˙˝ ˛˚˜ !"#$%&'(˜ )*˚ HCl HNO HClO NaOH KOH NHCl NaCl ˘ˇ ˆ ˙ ˝˛˙

=����# K� �#�-)!���� Bronsted-Lowry

•••• �#�������&I� H+ 100% )OP��#����

HCl + H2O H3O+ + Cl-

�#�������&I� H+ < 100% )OP��#�����

11

CH3COOH + H2O CH3COO- + H3O+

NH2- + H2O NH3 + OH-

•••• )!�#�! H+ ��� 100% )OP�)!����

)!�#�! H+ ��� < 100% )OP�)!�����

Page 12: ˘ˇ - Chem ku-kpschem.flas.kps.ku.ac.th/SLIDE/SLIDE-53-TEACHER-ION... · 1. strong electrolyte ˘ˇ˘ˆ˙˝ ˛˚˜ !"#$%&'(˜ )*˚ HCl HNO HClO NaOH KOH NHCl NaCl ˘ˇ ˆ ˙ ˝˛˙

=����# K� ="��#�-)!�

12

12

Page 13: ˘ˇ - Chem ku-kpschem.flas.kps.ku.ac.th/SLIDE/SLIDE-53-TEACHER-ION... · 1. strong electrolyte ˘ˇ˘ˆ˙˝ ˛˚˜ !"#$%&'(˜ )*˚ HCl HNO HClO NaOH KOH NHCl NaCl ˘ˇ ˆ ˙ ˝˛˙

1. Hydro acids O#9��!���� H ��9^����H8��7� 1 *�Y�

�<�I9&�=�!)�7�����N��=�� EN �" =����# �#�M9)]Y8�

=����# K� �#�

PH <<<< H S <<<< HCl

��"� 2 ;�<"=�>(?

13

PH3 <<<< H2S <<<< HCl

NH3 <<<< H2O <<<< HF

�<�I9I�"�)�7����� =����# �#�)]Y8� ������<���K� ]�� ��&���#����]��^9

HF<<<< HCl <<<< HBr <<<< HI(]�� ��&���#����]��^9�" 678���)

Page 14: ˘ˇ - Chem ku-kpschem.flas.kps.ku.ac.th/SLIDE/SLIDE-53-TEACHER-ION... · 1. strong electrolyte ˘ˇ˘ˆ˙˝ ˛˚˜ !"#$%&'(˜ )*˚ HCl HNO HClO NaOH KOH NHCl NaCl ˘ˇ ˆ ˙ ˝˛˙

2. Oxo acid O#9��!���� O, H ��9^����H8��7� 1 *�Y��#����<>678�7�9������ )I�H��������I�"�678��)��9��"��7M(�������)6����� =����# K� �#�)]Y8�KL'����)�K

���>Y)�*�� K� �9������ +1 +5

=����# K� �#�

14

���>Y)�*�� K� �9������

HClO <<<< HClO2 <<<< HClO3 <<<< HClO4

+1 +3 +5 +7

�9������ ��� *�Y���������"�&�I�"�)�7�������9�7)�K���>Y)�*�� )6����� =����# K� �#�M9)]Y8�KL'���� EN K� �9������ HlO4 <<<< HBrO4 <<<< HClO4

Page 15: ˘ˇ - Chem ku-kpschem.flas.kps.ku.ac.th/SLIDE/SLIDE-53-TEACHER-ION... · 1. strong electrolyte ˘ˇ˘ˆ˙˝ ˛˚˜ !"#$%&'(˜ )*˚ HCl HNO HClO NaOH KOH NHCl NaCl ˘ˇ ˆ ˙ ˝˛˙

1. �g�#���>�%K� <�I9I�"� IA )OP�)!����

<�I9K���&Ih�KL'� =����# )!�)]Y8� : KOH > NaOH

2. ������!�9���)�78��

=����# K� )!�

15

2. ������!�9���)�78��M(����O#9M������)]Y8�=����# )!�)]Y8� :

N 3- >>>> O2- >>>> F-

&�I�"�)�7����� =�� EN )]Y8�=����# )!�)]Y8� O2- >>>> S2-

&�=�!)�7�����=�� EN ��� M��K���O>���

=����# )!�)]Y8� NH2- >>>> OH- >>>> F-

Page 16: ˘ˇ - Chem ku-kpschem.flas.kps.ku.ac.th/SLIDE/SLIDE-53-TEACHER-ION... · 1. strong electrolyte ˘ˇ˘ˆ˙˝ ˛˚˜ !"#$%&'(˜ )*˚ HCl HNO HClO NaOH KOH NHCl NaCl ˘ˇ ˆ ˙ ˝˛˙

G �#����-)!���� ������ 100 %KOH K+ + OH-

1 mol 1 mol 1 mol�#���� )!����

��#������K� �#� - )!�

16

�#���� (Strong acids)

)!���� (Strong bases)

Group 1A (hydroxides)(NaOH, KOH, LiOH, etc.)Group 2A (hydroxides)Ca(OH)2, Mg(OH)2, Sr(OH)2, etc.)

)*�� HClO4, HCl, HBr, HI, HNO3, H2SO4

Page 17: ˘ˇ - Chem ku-kpschem.flas.kps.ku.ac.th/SLIDE/SLIDE-53-TEACHER-ION... · 1. strong electrolyte ˘ˇ˘ˆ˙˝ ˛˚˜ !"#$%&'(˜ )*˚ HCl HNO HClO NaOH KOH NHCl NaCl ˘ˇ ˆ ˙ ˝˛˙

G �#�����-)!����� �������������� 100 %()OP�OkY�Y#Y��l�����!)

��#������K� �#�����

HA + H2O H3O+ + A-

17

][

][][3

HA

AOHK a

−+

=

= =��= 678��#������K� �#�����K a

Page 18: ˘ˇ - Chem ku-kpschem.flas.kps.ku.ac.th/SLIDE/SLIDE-53-TEACHER-ION... · 1. strong electrolyte ˘ˇ˘ˆ˙˝ ˛˚˜ !"#$%&'(˜ )*˚ HCl HNO HClO NaOH KOH NHCl NaCl ˘ˇ ˆ ˙ ˝˛˙

G�#�<�<�<O#�Y�: �#� 1 <�)����������&I� H+ 1 ���

CH3COOH + H2O H3O++ CH3COO-

18

][

[][

3

33]

COOHCH

COOCHOHK a

−+

=

Page 19: ˘ˇ - Chem ku-kpschem.flas.kps.ku.ac.th/SLIDE/SLIDE-53-TEACHER-ION... · 1. strong electrolyte ˘ˇ˘ˆ˙˝ ˛˚˜ !"#$%&'(˜ )*˚ HCl HNO HClO NaOH KOH NHCl NaCl ˘ˇ ˆ ˙ ˝˛˙

C�#�<]�Y<O#�Y�: 1 <�)����������&I� H+ >>>> 1 ���

H3PO4 H2CO3 H2S

H3PO4 + H2O H3O++ H2PO4- K1

19

H2PO4- + H2O H3O++ HPO4

2- K2

HPO42- + H2O H3O++ PO4

3- K3

H3PO4 + 3H2O 3H3O++ PO43- Ka

Ka = K1 x K2 x K3

Page 20: ˘ˇ - Chem ku-kpschem.flas.kps.ku.ac.th/SLIDE/SLIDE-53-TEACHER-ION... · 1. strong electrolyte ˘ˇ˘ˆ˙˝ ˛˚˜ !"#$%&'(˜ )*˚ HCl HNO HClO NaOH KOH NHCl NaCl ˘ˇ ˆ ˙ ˝˛˙

NH3 + H2O NH4++ OH-

��#������K� )!�����

][][4

OHNHK

−+

=

20

][

][][

3

4

NH

OHNHK b

=

Page 21: ˘ˇ - Chem ku-kpschem.flas.kps.ku.ac.th/SLIDE/SLIDE-53-TEACHER-ION... · 1. strong electrolyte ˘ˇ˘ˆ˙˝ ˛˚˜ !"#$%&'(˜ )*˚ HCl HNO HClO NaOH KOH NHCl NaCl ˘ˇ ˆ ˙ ˝˛˙

��#������K� �'(� (Hydrolysis)

H2O + H2O H3O++ OH-

���� H2O H++ OH-

[ ]OHOH

OHOHK

3

][

][][−+

=

21

[ ]OHOHK

2][ 2

=

[ ] [ ] [ ]OHOHOHK−+=

32

2

[H2O] = � !"#

Kw = =��= 678l�="$�����K� �'(�

][][3

OHOHK w

−+=

Page 22: ˘ˇ - Chem ku-kpschem.flas.kps.ku.ac.th/SLIDE/SLIDE-53-TEACHER-ION... · 1. strong electrolyte ˘ˇ˘ˆ˙˝ ˛˚˜ !"#$%&'(˜ )*˚ HCl HNO HClO NaOH KOH NHCl NaCl ˘ˇ ˆ ˙ ˝˛˙

= 1.008x10-14 (mol dm-3)2 � 250CKw = 2.95x10-14 (mol dm-3)2 � 400C

678 250C [H3O+] = [OH- ] = 1.0x10-7 mol dm-3 )OP����

��#�9����#� [H O+] >>>> 10-7 mol dm-3

][][3

OHOHK w

−+=

22

��#�9����#� [H3O+] >>>> 10-7 mol dm-3

��#�9���)!� [H3O+] <<<< 10-7 mol dm-3

[OH- ] <<<< 10-7 mol dm-3

[OH- ] >>>> 10-7 mol dm-3

Page 23: ˘ˇ - Chem ku-kpschem.flas.kps.ku.ac.th/SLIDE/SLIDE-53-TEACHER-ION... · 1. strong electrolyte ˘ˇ˘ˆ˙˝ ˛˚˜ !"#$%&'(˜ )*˚ HCl HNO HClO NaOH KOH NHCl NaCl ˘ˇ ˆ ˙ ˝˛˙

]7)�* (pH)

���#����� pH (pH scale)

10][][

10][][

log

log33

pOH

pH

OHOHpOH

OHOHpH

−−−

−++

=⇒−=

=⇒−=

23

�'(�!#Y��6^Yq [H3O+] = [OH- ] = 1.0x10-7 mol dm-3

pH = - log (1.0x10-7 )

pH = 7 ()OP���� )[H3O

+] >>>> 10-7 mol dm-3 pH <<<< 7 )OP���#�9����#�[H3O

+] <<<< 10-7 mol dm-3 pH >>>> 7 )OP���#�9���)!�

Page 24: ˘ˇ - Chem ku-kpschem.flas.kps.ku.ac.th/SLIDE/SLIDE-53-TEACHER-ION... · 1. strong electrolyte ˘ˇ˘ˆ˙˝ ˛˚˜ !"#$%&'(˜ )*˚ HCl HNO HClO NaOH KOH NHCl NaCl ˘ˇ ˆ ˙ ˝˛˙

=������]�� %̂K� pH ��9 pOH

log

log

100.1

100.1][][

][

14

14

3

3

−=

==

−=

−−+

+

×

×

pH

OHOHK

OHpH

w

24

14

14

loglog

log

][10

][

100.1

14

=+

−=

−−=

−=

−−

−×

pOHpH

pOHpH

OHpH

OHpH

Page 25: ˘ˇ - Chem ku-kpschem.flas.kps.ku.ac.th/SLIDE/SLIDE-53-TEACHER-ION... · 1. strong electrolyte ˘ˇ˘ˆ˙˝ ˛˚˜ !"#$%&'(˜ )*˚ HCl HNO HClO NaOH KOH NHCl NaCl ˘ˇ ˆ ˙ ˝˛˙

��#=(���$I� pH������� ��#�9��� CO2 �Y8�����7 [H3O

+] = 1.3x10-4molL-1

M =(���$ pH K� ��#�9���

�Y 7̂6(� ][ 3log OHpH +−=

25

103.1log4× −

−=pH

89.3

411.0

43.1log

10log43.1log

=

+−=

+−=

+−=

Page 26: ˘ˇ - Chem ku-kpschem.flas.kps.ku.ac.th/SLIDE/SLIDE-53-TEACHER-ION... · 1. strong electrolyte ˘ˇ˘ˆ˙˝ ˛˚˜ !"#$%&'(˜ )*˚ HCl HNO HClO NaOH KOH NHCl NaCl ˘ˇ ˆ ˙ ˝˛˙

1. M I� [H3O+] K� ��#�9���678�7 pH = 4.4(antilog 0.6 = 4 antilog 0.4 = 2.5)

2. M =(���$ [H3O+] ��9 [OH-] K� ��#�9���678�7

pH = 4.5 (antilog 0.5 = 3.2)

�!!st�I��

26

3. M I� pH K� ��#�9��� 0.01 M NaOH

4. M I� pH K� ��#�9��� 0.001 M HCl

5. M I� pH K� ��#�9��� 0.2 MCH3COOH Ka=1.8x10-5

6. M I� pH K� ��#�9��� 0.2 M NH4OH Kb=1.8x10-5

pH = 4.5 (antilog 0.5 = 3.2)

Page 27: ˘ˇ - Chem ku-kpschem.flas.kps.ku.ac.th/SLIDE/SLIDE-53-TEACHER-ION... · 1. strong electrolyte ˘ˇ˘ˆ˙˝ ˛˚˜ !"#$%&'(˜ )*˚ HCl HNO HClO NaOH KOH NHCl NaCl ˘ˇ ˆ ˙ ˝˛˙

�� ���������������� �������

� ��#=(���$=�� pH K� ��#�9����#���� ��9)!���� � � � �

[H+] ��9 [OH-] )6����!=���)K��K��)#Y8����K� �#������9)!������'�

������� HCl )K��K�� 1.0 x 10-3 M M =(���$ [OH-].

27

HCl = strong acid : HCl →→→→ H+ + Cl-

[H+] = [HCl] = 1.0 x 10-3 M

Thus (1.0 x 10-3 )[OH- ]= 1.0 x 10-14

[OH- ] = 1.0 x 10-11

Page 28: ˘ˇ - Chem ku-kpschem.flas.kps.ku.ac.th/SLIDE/SLIDE-53-TEACHER-ION... · 1. strong electrolyte ˘ˇ˘ˆ˙˝ ˛˚˜ !"#$%&'(˜ )*˚ HCl HNO HClO NaOH KOH NHCl NaCl ˘ˇ ˆ ˙ ˝˛˙

�������� Calculate pOH and pH of 5.0 x 10-2 M NaOH.

[OH- ] = 5.0 x 10-2 M

�! ����� NaOH = strong base

pOH = - log (5.0 x 10-2 ) = 1.30

28

pOH = - log (5.0 x 10 ) = 1.30

[H+] = = 2.0 x 10-131.0 x10-14

5.0 x 10-2

pH = -log (2.0 x 10-13) = 12.70

pOH + pH = 1.30 + 12.70 = 14.00

Page 29: ˘ˇ - Chem ku-kpschem.flas.kps.ku.ac.th/SLIDE/SLIDE-53-TEACHER-ION... · 1. strong electrolyte ˘ˇ˘ˆ˙˝ ˛˚˜ !"#$%&'(˜ )*˚ HCl HNO HClO NaOH KOH NHCl NaCl ˘ˇ ˆ ˙ ˝˛˙

�������� Calculate pH of solution prepared by mixing 2.0 mL of a strong acid of pH 3.00 and 3.0 mL of a strong base of pH 10.0

[H+] of strong acid solution = 1.0 x 10-3 M

mmol H+ = 1.0 x 10-3 M x 2.0 mL

29

mmol H+ = 1.0 x 10-3 M x 2.0 mL

= 2.0 x 10-3 mmol

pOH of strong base solution = 14.00 - 10.00 = 4.00

[OH- ] = 1.0 x 10-4 M

Page 30: ˘ˇ - Chem ku-kpschem.flas.kps.ku.ac.th/SLIDE/SLIDE-53-TEACHER-ION... · 1. strong electrolyte ˘ˇ˘ˆ˙˝ ˛˚˜ !"#$%&'(˜ )*˚ HCl HNO HClO NaOH KOH NHCl NaCl ˘ˇ ˆ ˙ ˝˛˙

mmol OH- = 1.0 x 10-4 M x 3.0 mL

= 3.0 x 10-4 mmol

excess acid ,

mmol H+ = 0.0020 - 0.0003

30

mmol H = 0.0020 - 0.0003

= 0.0017 mmol

[H+] = 0.0017 mmol / 5.0 mL = 3.4 x 10-4 M

pH = -log ( 3.4 x 10-4 ) = 3.47

Page 31: ˘ˇ - Chem ku-kpschem.flas.kps.ku.ac.th/SLIDE/SLIDE-53-TEACHER-ION... · 1. strong electrolyte ˘ˇ˘ˆ˙˝ ˛˚˜ !"#$%&'(˜ )*˚ HCl HNO HClO NaOH KOH NHCl NaCl ˘ˇ ˆ ˙ ˝˛˙

��#=(���$678)�78����! �#����� )!����� ��9)��H�K� �#�������9)��H�K� )!�����

Weak Acids and Bases.

- weak acids (or bases) are only partially ionized.

- amount of ionization , pH can be calculated from

31

- amount of ionization , pH can be calculated from

Kaor Kb.

Page 32: ˘ˇ - Chem ku-kpschem.flas.kps.ku.ac.th/SLIDE/SLIDE-53-TEACHER-ION... · 1. strong electrolyte ˘ˇ˘ˆ˙˝ ˛˚˜ !"#$%&'(˜ )*˚ HCl HNO HClO NaOH KOH NHCl NaCl ˘ˇ ˆ ˙ ˝˛˙

������� ��#�9����#� HCN 0.2 M ������&I�[H3O

+] 4.0x10-3 M M I�=�� Ka

HCN + H2O H3O+ + CN-

)#Y8���� 0.2 M

678�����- -

4.0x10-3M 4.0x10-3M(0.2- 4.0x10-3 M)

32

678����� 4.0x10-3M 4.0x10-3M(0.2- 4.0x10-3 M)

][

][][ 3

HCN

CNOHK a

−+

=

1016.8]004.02.0[

004.0004.0 5×−× −==K a

Page 33: ˘ˇ - Chem ku-kpschem.flas.kps.ku.ac.th/SLIDE/SLIDE-53-TEACHER-ION... · 1. strong electrolyte ˘ˇ˘ˆ˙˝ ˛˚˜ !"#$%&'(˜ )*˚ HCl HNO HClO NaOH KOH NHCl NaCl ˘ˇ ˆ ˙ ˝˛˙

��#=(���$)�78����!=�� Ka ��9 Kb

������� M I� [H+] &���#�9��� CH3COOH)K��K�� 1.0 mol dm-3 678 250C Ka = 1.8x10

-5

CH3COOH + H2O H3O++ CH3COO-

- -)#Y8���� 1.0 M

33

- -x M x M(1.0- x M)

)#Y8���� 1.0 M678�����

Ka =

1.8x10-5 =(x) (x) (1.0 - x)

[H3O+] [CH3COO- ]

[CH3COOH]

Page 34: ˘ˇ - Chem ku-kpschem.flas.kps.ku.ac.th/SLIDE/SLIDE-53-TEACHER-ION... · 1. strong electrolyte ˘ˇ˘ˆ˙˝ ˛˚˜ !"#$%&'(˜ )*˚ HCl HNO HClO NaOH KOH NHCl NaCl ˘ˇ ˆ ˙ ˝˛˙

M9��� x = -b ±±±± b2 y 4ac 2a

x2 + (1.8x10-5)x - 1.8x10-5 = 0

34

2a

�6�=�� a = 1, b = 1.8x10-5, c = - 1.8x10-5

M9��� x = 4.2 x 10-3 mol dm-3

[H+] = 4.2 x 10-3 mol dm-3

Page 35: ˘ˇ - Chem ku-kpschem.flas.kps.ku.ac.th/SLIDE/SLIDE-53-TEACHER-ION... · 1. strong electrolyte ˘ˇ˘ˆ˙˝ ˛˚˜ !"#$%&'(˜ )*˚ HCl HNO HClO NaOH KOH NHCl NaCl ˘ˇ ˆ ˙ ˝˛˙

)�H8� M�� [H+] �7=���������)�H8�)67�!��!=��� )K��K��)#Y8���� ��M���=�� x &�)6�� 1.00-x ������

1.8x10-5 =(x) (x) (1.0 - x) =

(x) (x) (1.0)

x2 = 1.8x10-5

35

x2 = 1.8x10-5

x = √√√√1.8x10-5 = 4.2 x 10-3 mol dm-3

% ��#������ = 4.2 x 10-3 x100 = 0.421

Page 36: ˘ˇ - Chem ku-kpschem.flas.kps.ku.ac.th/SLIDE/SLIDE-53-TEACHER-ION... · 1. strong electrolyte ˘ˇ˘ˆ˙˝ ˛˚˜ !"#$%&'(˜ )*˚ HCl HNO HClO NaOH KOH NHCl NaCl ˘ˇ ˆ ˙ ˝˛˙

������������������� ��(� 5% ������ +��+�����#��#����<���� ���� [HA]/Ka > 1000=����"��<��S��������� (x) $�� HA �"�

CH COOH + H O H O++ CH COO-

�%&'(�)*

36

CH3COOH + H2O H3O++ CH3COO-

)#Y8���� 1.0 M - -

678����� x M x M(1.0- x M) ≅≅≅≅ 1.0

Page 37: ˘ˇ - Chem ku-kpschem.flas.kps.ku.ac.th/SLIDE/SLIDE-53-TEACHER-ION... · 1. strong electrolyte ˘ˇ˘ˆ˙˝ ˛˚˜ !"#$%&'(˜ )*˚ HCl HNO HClO NaOH KOH NHCl NaCl ˘ˇ ˆ ˙ ˝˛˙

7. Salts of Weak Acids and Bases.

- salt of weak acid is a strong electrolyte.

- salt of weak acid is a Bronsted base.

Example NaA Na+ + A-

37

Example NaA Na + A

A- + H2O HA + OH- ---------- 1

( Bronsted base)

Equilibrium for these Bronsted base are identically to the weak base.

Page 38: ˘ˇ - Chem ku-kpschem.flas.kps.ku.ac.th/SLIDE/SLIDE-53-TEACHER-ION... · 1. strong electrolyte ˘ˇ˘ˆ˙˝ ˛˚˜ !"#$%&'(˜ )*˚ HCl HNO HClO NaOH KOH NHCl NaCl ˘ˇ ˆ ˙ ˝˛˙

So, KH = Kb = ---------- 2

KH = hydrolysis constant of the sale = Kb

K can be calculated form K

[HA] [OH-]

[A-]

38

Kb can be calculated form Ka

The product of Ka of any weak acid and Kb of its conjugate base is always equal to Kw.

KaKb = Kw

Page 39: ˘ˇ - Chem ku-kpschem.flas.kps.ku.ac.th/SLIDE/SLIDE-53-TEACHER-ION... · 1. strong electrolyte ˘ˇ˘ˆ˙˝ ˛˚˜ !"#$%&'(˜ )*˚ HCl HNO HClO NaOH KOH NHCl NaCl ˘ˇ ˆ ˙ ˝˛˙

So , from 2 = = Kb ---------- 3

: The pH of a salt (Bronsted base) is calculated as same as weak base.

Kw

Ka

[HA] [OH-]

[A-]

39

weak base.

If concentration of A is CA- .

A- + H2O HA + OH-

(CA- - X) X X

Page 40: ˘ˇ - Chem ku-kpschem.flas.kps.ku.ac.th/SLIDE/SLIDE-53-TEACHER-ION... · 1. strong electrolyte ˘ˇ˘ˆ˙˝ ˛˚˜ !"#$%&'(˜ )*˚ HCl HNO HClO NaOH KOH NHCl NaCl ˘ˇ ˆ ˙ ˝˛˙

: The quantity X can be neglected compared to CA- if CA- > 100 Kb.

from 3 = = Kb

[OH-] [OH- ]

CA-

Kw

Ka

40

[OH- ] = . CA- = Kb . CA- -------- 4

4 holds only if CA- > 100 Kb

Kw

Ka

Page 41: ˘ˇ - Chem ku-kpschem.flas.kps.ku.ac.th/SLIDE/SLIDE-53-TEACHER-ION... · 1. strong electrolyte ˘ˇ˘ˆ˙˝ ˛˚˜ !"#$%&'(˜ )*˚ HCl HNO HClO NaOH KOH NHCl NaCl ˘ˇ ˆ ˙ ˝˛˙

�������� Calculate the pH of 0.10 M solution of Sodium acetate.

NaOAc Na+ + OAc- (ionized)

OAc- + H2O HOAc + OH- (hydrolysis)

41

= Kb = = [HOAc] [OH- ]

[OAc- ]

Kw

Ka

1.00 x 10-14

1.75 x 10-5

= 5.7 x 10-10

Page 42: ˘ˇ - Chem ku-kpschem.flas.kps.ku.ac.th/SLIDE/SLIDE-53-TEACHER-ION... · 1. strong electrolyte ˘ˇ˘ˆ˙˝ ˛˚˜ !"#$%&'(˜ )*˚ HCl HNO HClO NaOH KOH NHCl NaCl ˘ˇ ˆ ˙ ˝˛˙

[HOAc] = [OH- ] = X

[OAc- ] = COAc - X = 0.10 - X

since COAc >>> Kb neglected X compared to COAc , Then

= 5.7 x 10-10 (X)(X)

42

= 5.7 x 10-10

X = 5.7 x 10-10 x 0.10 = 7.6 x 10-6 = [OH- ]

( compared the solution to equation 4 )

(X)(X)

0.10

Page 43: ˘ˇ - Chem ku-kpschem.flas.kps.ku.ac.th/SLIDE/SLIDE-53-TEACHER-ION... · 1. strong electrolyte ˘ˇ˘ˆ˙˝ ˛˚˜ !"#$%&'(˜ )*˚ HCl HNO HClO NaOH KOH NHCl NaCl ˘ˇ ˆ ˙ ˝˛˙

[OH- ] = 7.6 x 10-6 M

[H+] = = 1.3 x 10-9

pH = -log 1.3 x 10-9 = 8.89

1.0 x 10-14

7.6 x 10-6

43

Problem : Calculate the pH of a 0.25 M solution of ammonium chloride. ( Kb of NH3 = 1.75 x 10

-5 )

Page 44: ˘ˇ - Chem ku-kpschem.flas.kps.ku.ac.th/SLIDE/SLIDE-53-TEACHER-ION... · 1. strong electrolyte ˘ˇ˘ˆ˙˝ ˛˚˜ !"#$%&'(˜ )*˚ HCl HNO HClO NaOH KOH NHCl NaCl ˘ˇ ˆ ˙ ˝˛˙

8. Buffer Buffer : a solution that resists change in pH.

add a small amount of acid.

When add a small amount of base.

44

Solution is dilute.

Buffer solution mixture of a weak acid and its conjugate base. mixture of a weak base and its conjugate acid.

Page 45: ˘ˇ - Chem ku-kpschem.flas.kps.ku.ac.th/SLIDE/SLIDE-53-TEACHER-ION... · 1. strong electrolyte ˘ˇ˘ˆ˙˝ ˛˚˜ !"#$%&'(˜ )*˚ HCl HNO HClO NaOH KOH NHCl NaCl ˘ˇ ˆ ˙ ˝˛˙

Consider an HA / A- buffer . HA H+ + A-

When add A- into system, so, [H+ ] = [A- ]

[H+] = Ka

-log [H+] = -logKa - log

[HA] [A- ]

[HA] [A- ]

45

-log [H ] = -logKa - log

pH = pKa - log [A- ]

[HA] [A- ]

[A- ] [HA]

pH = pKa + log

(Henderson - Hasselbalch equation)

Page 46: ˘ˇ - Chem ku-kpschem.flas.kps.ku.ac.th/SLIDE/SLIDE-53-TEACHER-ION... · 1. strong electrolyte ˘ˇ˘ˆ˙˝ ˛˚˜ !"#$%&'(˜ )*˚ HCl HNO HClO NaOH KOH NHCl NaCl ˘ˇ ˆ ˙ ˝˛˙

The pH of a buffer is determined by the ratio of the conjugate acid - base pair concentration.

pH = pKa + log

pH = pK + log

[conjugate base] [acid]

[proton acceptor]

46

pH = pKa + log

�������� Calculate the pH of a buffer prepared by adding 10 ml of 0.10 M acetic acid to 20 mL of 0.10 M Sodium acetate.

[proton acceptor] [proton donor]

Page 47: ˘ˇ - Chem ku-kpschem.flas.kps.ku.ac.th/SLIDE/SLIDE-53-TEACHER-ION... · 1. strong electrolyte ˘ˇ˘ˆ˙˝ ˛˚˜ !"#$%&'(˜ )*˚ HCl HNO HClO NaOH KOH NHCl NaCl ˘ˇ ˆ ˙ ˝˛˙

For HOAc,0.10 mmol / mL x 10 mL = MHOAc x 30 mLMHOAc = 0.033 mmol / mL

For OAc-,0.10 mmol / mL x 20 mL = MOAc- x 30 mL

0 067

47

0.10 mmol / mL x 20 mL = MOAc x 30 mLMOAc- = 0.067 mmol / mL

[HOAc] [OAc- ] at equilibrium 0.033 - X 0.067 + X

=0.033 = 0.067

0 0

Page 48: ˘ˇ - Chem ku-kpschem.flas.kps.ku.ac.th/SLIDE/SLIDE-53-TEACHER-ION... · 1. strong electrolyte ˘ˇ˘ˆ˙˝ ˛˚˜ !"#$%&'(˜ )*˚ HCl HNO HClO NaOH KOH NHCl NaCl ˘ˇ ˆ ˙ ˝˛˙

pH = -logKa + log

= - log(1.75 x 10-5) + log

= 4.76 + log 2.0

[proton acceptor] [proton donor]

0.067 mmol / mL 0.033 mmol / mL

48

= 5.06

�������� Calculate the pH of a solution prepared by adding 25 mL of 0.10 M Sodium hydroxide to 30 mL of 0.20 M acetic acid.

Page 49: ˘ˇ - Chem ku-kpschem.flas.kps.ku.ac.th/SLIDE/SLIDE-53-TEACHER-ION... · 1. strong electrolyte ˘ˇ˘ˆ˙˝ ˛˚˜ !"#$%&'(˜ )*˚ HCl HNO HClO NaOH KOH NHCl NaCl ˘ˇ ˆ ˙ ˝˛˙

mmol HOAc = 0.20 M x 30 mL = 6.0 mmolmmol NaOH = 0.10 M x 25 mL = 2.5 mmol

These react as Follows :

HOAc + NaOH NaOAc + H2OAfter reaction,

49

After reaction,mmol NaOAc = 2.5 mmolmmol HOAc = 6.0 - 2.5 = 3.5 mmol

pH = 4.76 + log = 4.612.5 3.5

Page 50: ˘ˇ - Chem ku-kpschem.flas.kps.ku.ac.th/SLIDE/SLIDE-53-TEACHER-ION... · 1. strong electrolyte ˘ˇ˘ˆ˙˝ ˛˚˜ !"#$%&'(˜ )*˚ HCl HNO HClO NaOH KOH NHCl NaCl ˘ˇ ˆ ˙ ˝˛˙

• pH ��(��� ����)������� ���U���� ��#�9���!�:):�#% 1 �Y�# �7 CH3COOH 0.1 mol ��9CH3COONa 0 .1 mol

+&�(),%+�-.+/-(01.+/23045(5��6

][ COOHCH

50

][

][

3

3log

COOCH

COOHCHpK

apH

−−=

( )( )

745.4

1.0

1.0log745.4

=

−=

Page 51: ˘ˇ - Chem ku-kpschem.flas.kps.ku.ac.th/SLIDE/SLIDE-53-TEACHER-ION... · 1. strong electrolyte ˘ˇ˘ˆ˙˝ ˛˚˜ !"#$%&'(˜ )*˚ HCl HNO HClO NaOH KOH NHCl NaCl ˘ˇ ˆ ˙ ˝˛˙

�<V�<" HCl 1.0 M 1 cm3 �$�����Y�� = 0.001 mol

CH3COOH + H2O H3O++ CH3COO-

N��)�Y� HCl 1.0 M O#Y���# 1 cm3 M96(�&I���#�9����7 pH )6���#

51

CH3COOH + H2O H3O + CH3COO

H+ + CH3COO- CH3COOH

HCl H++ Cl-

0.001mol �" 0.001mol ��<� 0.001mol

Page 52: ˘ˇ - Chem ku-kpschem.flas.kps.ku.ac.th/SLIDE/SLIDE-53-TEACHER-ION... · 1. strong electrolyte ˘ˇ˘ˆ˙˝ ˛˚˜ !"#$%&'(˜ )*˚ HCl HNO HClO NaOH KOH NHCl NaCl ˘ˇ ˆ ˙ ˝˛˙

)�H8�)�Y� HCl ������� =Y�=���)K��K��&I��

( )

( )L

mol

L

mol

L

mol

L

mol

COOCH

COOHCH

099.0001.1

001.01.0

101.0001.1

001.01.0

][

][

3

3

=−

=

=+

=

52

$��

(pH =����� )�"<�)

][

][

3

3log

COOCH

COOHCHpK

apH

−−=

736.4

009.0745.4

099.0

101.0log745.4

=

−=

−=

Page 53: ˘ˇ - Chem ku-kpschem.flas.kps.ku.ac.th/SLIDE/SLIDE-53-TEACHER-ION... · 1. strong electrolyte ˘ˇ˘ˆ˙˝ ˛˚˜ !"#$%&'(˜ )*˚ HCl HNO HClO NaOH KOH NHCl NaCl ˘ˇ ˆ ˙ ˝˛˙

•••• N��)�Y� NaOH 1.0 M O#Y���# 1 cm3 M96(�&I���#�9����7 pH )6���#

CH3COOH + H2O H3O++ CH3COO-

NaOH Na++ OH-

OH- + CH COOH CH COO- + H O

53

0.001 mol

)�H8�)�Y� NaOH ����=���)K��K��K� ��#)O�78���O

M(����<��K� NaOH 678)�Y� =

OH- + CH3COOH CH3COO- + H2O

Page 54: ˘ˇ - Chem ku-kpschem.flas.kps.ku.ac.th/SLIDE/SLIDE-53-TEACHER-ION... · 1. strong electrolyte ˘ˇ˘ˆ˙˝ ˛˚˜ !"#$%&'(˜ )*˚ HCl HNO HClO NaOH KOH NHCl NaCl ˘ˇ ˆ ˙ ˝˛˙

0.001mol �� 0.001mol ����� 0.001mol( )

( ) molmol

L

mol

L

mol

COOCH

COOHCH

101.0001.01.0

099.0001.1

001.01.0

][

][3

=+

=

=−

=

OH- + CH3COOH CH3COO- + H2O

54

LLCOOCH 101.0

001.1][

3==

(pH =����� )�"<�)

][

][

3

3log

COOCH

COOHCHpK

apH

−−=

749.4

101.0

099.0log745.4

=

−=

Page 55: ˘ˇ - Chem ku-kpschem.flas.kps.ku.ac.th/SLIDE/SLIDE-53-TEACHER-ION... · 1. strong electrolyte ˘ˇ˘ˆ˙˝ ˛˚˜ !"#$%&'(˜ )*˚ HCl HNO HClO NaOH KOH NHCl NaCl ˘ˇ ˆ ˙ ˝˛˙

� !�"��#$% &#' !�(� )*+,�,-!.

H2O H++ OH-)�Y��'(�

CH3COOH + H2O H3O++ CH3COO-

55

•••• =���)K��K��K� �������� ~ = )�Y� pH ML = 678

CH3COO- + H+ CH3COOH

CH3COOH + OH- H2O + CH3COO-

Page 56: ˘ˇ - Chem ku-kpschem.flas.kps.ku.ac.th/SLIDE/SLIDE-53-TEACHER-ION... · 1. strong electrolyte ˘ˇ˘ˆ˙˝ ˛˚˜ !"#$%&'(˜ )*˚ HCl HNO HClO NaOH KOH NHCl NaCl ˘ˇ ˆ ˙ ˝˛˙

� !�"!/)�' !�(� )*+,�,-!.

•••• )�H���#� I#H�)!�678�7 pKa I#H� pKb &���)=7� ��!pH I#H� pOH 678��� ��# I#H���"�&� *�� pKa ±±±± 1 I#H�

pKb ±±±± 1 )*��][

logHA

pKpH −=

56

][

][log

A

HApK

apH

−−=

I#H�[ ][ ]�����

��" [ ][ ]��"

�����1

10

10

1−≈

Page 57: ˘ˇ - Chem ku-kpschem.flas.kps.ku.ac.th/SLIDE/SLIDE-53-TEACHER-ION... · 1. strong electrolyte ˘ˇ˘ˆ˙˝ ˛˚˜ !"#$%&'(˜ )*˚ HCl HNO HClO NaOH KOH NHCl NaCl ˘ˇ ˆ ˙ ˝˛˙

������)������ �+� � ��Z$����"�(��Y" =��������� � [H3O+] = 3.3 x 10-2 M�(��$��������";�<"=" �(�����

HNO , K = 4.6x10-4

)47�'/& +&�()�"'%1&�898&'045(5��6

57

HNO2, Ka = 4.6x10-4

H3PO4, Ka = 7.5x10-3

HSO4-, Ka = 1.2x10-2

�#�678)�H��&*�=H�.........................?

Page 58: ˘ˇ - Chem ku-kpschem.flas.kps.ku.ac.th/SLIDE/SLIDE-53-TEACHER-ION... · 1. strong electrolyte ˘ˇ˘ˆ˙˝ ˛˚˜ !"#$%&'(˜ )*˚ HCl HNO HClO NaOH KOH NHCl NaCl ˘ˇ ˆ ˙ ˝˛˙

HSO4- + H2O H3O+ + SO4

2 -

•••• M��=�� Ka )�H��&*� HSO4- ��9O#�!���#�����

#9I��� �#���9)��H�

[ ]=+

−HSO

58

��� &*� HSO4- M(���� 2.7 <�� l����!)��H� SO4

2- M(����1 <��

[ ][ ]

[ ][ ] 1

75.2

102.1

103.3][

][

2

23

2

4

24

4

3

4

=××=

+=

=+

K a

OH

SO

HSO

SO

HSOK aOH

Page 59: ˘ˇ - Chem ku-kpschem.flas.kps.ku.ac.th/SLIDE/SLIDE-53-TEACHER-ION... · 1. strong electrolyte ˘ˇ˘ˆ˙˝ ˛˚˜ !"#$%&'(˜ )*˚ HCl HNO HClO NaOH KOH NHCl NaCl ˘ˇ ˆ ˙ ˝˛˙

������� M I����#�����M(����<��K� �#��9>Y�Y�(CH3COOH) ��9<>)�7���9>Y)�� (CH3COONa) )]H8�)�#7��!�:):�#%678�7 pH = 5.7 (Ka = 1.8x10-5)

loglog7.5

log

][

][

][

][

3

3

3

3

−−=

−=

× −

pH

COOCH

COOHCH

COOCH

COOHCHpK

a

101.8 5

59

)95.0log(

95.07.575.4log

log75.47.5

][

][

][

][

][

][

][

3

3

3

3

3

3

3

−=

−=−=

−−=

antiCOOCH

COOHCH

COOCH

COOHCH

COOCH

COOHCH

COOCH101.8

11.0

101.11)05.01log(

=× −=+−= anti

Page 60: ˘ˇ - Chem ku-kpschem.flas.kps.ku.ac.th/SLIDE/SLIDE-53-TEACHER-ION... · 1. strong electrolyte ˘ˇ˘ˆ˙˝ ˛˚˜ !"#$%&'(˜ )*˚ HCl HNO HClO NaOH KOH NHCl NaCl ˘ˇ ˆ ˙ ˝˛˙

������� M =(���$ pH K� !�:):�#% 0.4 M CH3COOH +0.4 M CH3COONa (Ka =1.8x10-5)

�Y 7̂6(� ][3

logCOOHCH

pKpH −=

60

�Y 7̂6(�][

][

3

3log

COOCH

COOHCHpK

apH

−−=

4.75101.8

101.85

5

=

−=

−−=

×

×−

log

4.0

4.0loglog

Page 61: ˘ˇ - Chem ku-kpschem.flas.kps.ku.ac.th/SLIDE/SLIDE-53-TEACHER-ION... · 1. strong electrolyte ˘ˇ˘ˆ˙˝ ˛˚˜ !"#$%&'(˜ )*˚ HCl HNO HClO NaOH KOH NHCl NaCl ˘ˇ ˆ ˙ ˝˛˙

������� M =(���$ pH K� !�:):�#%#9I��� 0.1 M NH3

400 cm3 ��9 0.2 M NH4NO3 400 cm3 (Kb=1.8x10-5)

0.1 M NH3 400 cm3 �$�����Y��

0.2 M NH4NO3 400 cm3 �$�����Y��

��<������� = 400+400 = 800 cm3

mol1000

4001.0 ×=

mol1000

4002.0 ×=

61

��<������� = 400+400 = 800 cm3

[ ]

[ ] 01.0800

1000

1000

4002.0

05.0800

1000

1000

4001.0

34

3

=××

=

=××

=

NONH

NH �6�=��&�����#(Henderson - Hasselbalch equation)

Page 62: ˘ˇ - Chem ku-kpschem.flas.kps.ku.ac.th/SLIDE/SLIDE-53-TEACHER-ION... · 1. strong electrolyte ˘ˇ˘ˆ˙˝ ˛˚˜ !"#$%&'(˜ )*˚ HCl HNO HClO NaOH KOH NHCl NaCl ˘ˇ ˆ ˙ ˝˛˙

�Y��Y)=)��#% (Indicator)

•••• ��#�Y�6#7�%678�7<=# �#�� >�!>�����9)O�78���7���

)�H8� pH K� ��#�9���)O�78��HIn (+�-�/�3) H+ + In -

�� �'(�) Y�

62

HIn (+�-�/�3) H + In�� �'(�) Y�

][

]][[

HIn

InHK In

−+

=

Page 63: ˘ˇ - Chem ku-kpschem.flas.kps.ku.ac.th/SLIDE/SLIDE-53-TEACHER-ION... · 1. strong electrolyte ˘ˇ˘ˆ˙˝ ˛˚˜ !"#$%&'(˜ )*˚ HCl HNO HClO NaOH KOH NHCl NaCl ˘ˇ ˆ ˙ ˝˛˙

�#�)������� #]����+ [In-] / [HIn]

��#�9����7�'(�) Y�

��#)O�78���7K� �Y��Y)=)��#%

10][=

−In

63

��#�9����7�'(�) Y�

��#�9����7��

1][=

HIn

10

1

][

][=

HIn

In

Page 64: ˘ˇ - Chem ku-kpschem.flas.kps.ku.ac.th/SLIDE/SLIDE-53-TEACHER-ION... · 1. strong electrolyte ˘ˇ˘ˆ˙˝ ˛˚˜ !"#$%&'(˜ )*˚ HCl HNO HClO NaOH KOH NHCl NaCl ˘ˇ ˆ ˙ ˝˛˙

���"�`�<����

pH ≤≤≤≤ 5 �7�7�� pH ≥≥≥≥ 8 �7�7�'(�) Y�

pH 5 - 8 �7�7l��#9I��� �� ��!�'(�) Y�&I� KIn K� �Y���� = 10-7

−+

64

&I� KIn K� �Y���� = 10

][

][

]

][

]][

][

]][

[

10

[10

[

7

7

HIn

HIn

HIn

In

H

InH

InHK In

+

−+−

−+

=

=

=

Page 65: ˘ˇ - Chem ku-kpschem.flas.kps.ku.ac.th/SLIDE/SLIDE-53-TEACHER-ION... · 1. strong electrolyte ˘ˇ˘ˆ˙˝ ˛˚˜ !"#$%&'(˜ )*˚ HCl HNO HClO NaOH KOH NHCl NaCl ˘ˇ ˆ ˙ ˝˛˙

N�� pH = 5, [H+] = 10-5 mol dm-3

)�H8� pH<5, [HIn] >>>> [In- ] 100 )6�� ML �7�7�� ][

][

100

1

]10[

105

7

HIn

In−

==

���"�`�<����

65

)�H8� pH<5, [HIn] >>>> [In ] 100 )6�� ML �7�7��

][

][

1

10

]10[

108

7

HIn

In−

==

N�� pH = 8, [H+] = 10-8 mol dm-3

)�H8� pH>8, [In- ] >>>> [HIn] 10 )6�� ML �7�7�'(�) Y�

Page 66: ˘ˇ - Chem ku-kpschem.flas.kps.ku.ac.th/SLIDE/SLIDE-53-TEACHER-ION... · 1. strong electrolyte ˘ˇ˘ˆ˙˝ ˛˚˜ !"#$%&'(˜ )*˚ HCl HNO HClO NaOH KOH NHCl NaCl ˘ˇ ˆ ˙ ˝˛˙

���� (�)�<�"<������ZIndicator pH �7678)O�78��

Thymol blue 1.2-2.8 �� -)I�H�

Bromphenol blue 3.0-4.6 )I�H� -�'(�) Y�

Congo red 3.0-5.0 �'(�) Y�-��

66

Congo red 3.0-5.0 �'(�) Y�-��

Methyl orange 3.1-4.4 �� -)I�H�

Bromocresol green 3.8-5.4 )I�H� -�'(�) Y�

Page 67: ˘ˇ - Chem ku-kpschem.flas.kps.ku.ac.th/SLIDE/SLIDE-53-TEACHER-ION... · 1. strong electrolyte ˘ˇ˘ˆ˙˝ ˛˚˜ !"#$%&'(˜ )*˚ HCl HNO HClO NaOH KOH NHCl NaCl ˘ˇ ˆ ˙ ˝˛˙

Indicator pH �7678)O�78��

Methyl red 4.2-6.3 �� -)I�H�

Azolitmin (litmus) 5.0-8.0 �� -�'(�) Y�

������� �Y��Y)=)��#%

67

Bromocresol purple 5.2-6.8 )I�H� -���

Bromthymol blue 6.0-7.6 )I�H� -�'(�) Y�

Phenol red 6.8-8.4 )I�H� - ��

Phenolphthalein 8.3-10.0 ����7�7-*�]"

Page 68: ˘ˇ - Chem ku-kpschem.flas.kps.ku.ac.th/SLIDE/SLIDE-53-TEACHER-ION... · 1. strong electrolyte ˘ˇ˘ˆ˙˝ ˛˚˜ !"#$%&'(˜ )*˚ HCl HNO HClO NaOH KOH NHCl NaCl ˘ˇ ˆ ˙ ˝˛˙

)OP���#�Y)=#�9I%I�O#Y��$��#I#H�=���)K��K��K� ��#�9��� <����#�(���#�9���678��� ��#�Y)=#�9I%��6(�OkY�Y#Y����!��#6786#�!=��� )K��K��678�������

��#�6)6#� (Titration)

68

��#6786#�!=���)K��K��678������ )#7�������#�9������#��� (Standard solution)

Page 69: ˘ˇ - Chem ku-kpschem.flas.kps.ku.ac.th/SLIDE/SLIDE-53-TEACHER-ION... · 1. strong electrolyte ˘ˇ˘ˆ˙˝ ˛˚˜ !"#$%&'(˜ )*˚ HCl HNO HClO NaOH KOH NHCl NaCl ˘ˇ ˆ ˙ ˝˛˙

+&�=!(!�)�9�7/& +�--(01

•••• )�H8��#�-)!�6(�OkY�Y#Y��������"�]��7 )#7��>?,+,�,'&19(!,3�9�7/& +�--(01

•••• M��678��# 2 *�Y�6(�OkY�Y#Y�����]��7 : @*-1%%A8

•••• M��678��#�9���)O�78���7 ()�Y�M�� indicator) : @*-'*),

69

•••• M��678��#�9���)O�78���7 ()�Y�M�� indicator) : @*-'*),

•••• I� pH K� ��#�9���#9I��� ��#�6)6#�M��- ��#������� pH meter- ��#=(���$- Titration curve #9I��� pH ��! O#Y���#

Page 70: ˘ˇ - Chem ku-kpschem.flas.kps.ku.ac.th/SLIDE/SLIDE-53-TEACHER-ION... · 1. strong electrolyte ˘ˇ˘ˆ˙˝ ˛˚˜ !"#$%&'(˜ )*˚ HCl HNO HClO NaOH KOH NHCl NaCl ˘ˇ ˆ ˙ ˝˛˙

+&�=!(!�)�9�7/& +�-.+/-(01.+/

(1.0M HCl 25 mL+ 1.0 M NaOH) $ M�����"� pH =7

pH range 5-9G Phenol red6.8-8.4

70

6.8-8.4 (yellow- red)G Bromthylmol blue 6.0-7.6

(yellow y blue)

Page 71: ˘ˇ - Chem ku-kpschem.flas.kps.ku.ac.th/SLIDE/SLIDE-53-TEACHER-ION... · 1. strong electrolyte ˘ˇ˘ˆ˙˝ ˛˚˜ !"#$%&'(˜ )*˚ HCl HNO HClO NaOH KOH NHCl NaCl ˘ˇ ˆ ˙ ˝˛˙

+&�=!(!�)�9�7/& +�-�/�3-(01.+/

0.1 M CH3COOH 25 mL + 0.1 M NaOH $ M�����"�pH = 9

pH range 8-10

71

pH range 8-10Phenolphthalein8.3-10.0(no color y pink)

Page 72: ˘ˇ - Chem ku-kpschem.flas.kps.ku.ac.th/SLIDE/SLIDE-53-TEACHER-ION... · 1. strong electrolyte ˘ˇ˘ˆ˙˝ ˛˚˜ !"#$%&'(˜ )*˚ HCl HNO HClO NaOH KOH NHCl NaCl ˘ˇ ˆ ˙ ˝˛˙

1.0 M NH3 40 mL + 1.0 M HCl $ M�����"� pH ≈≈≈≈ 5

��#�6)6#�#9I��� �#����-)!�����

pH range 4-7G Methyl red4.2-6.3

72

4.2-6.3 red-yellow

G Bromocresolgreen 3.8-5.4yellow-blue

Page 73: ˘ˇ - Chem ku-kpschem.flas.kps.ku.ac.th/SLIDE/SLIDE-53-TEACHER-ION... · 1. strong electrolyte ˘ˇ˘ˆ˙˝ ˛˚˜ !"#$%&'(˜ )*˚ HCl HNO HClO NaOH KOH NHCl NaCl ˘ˇ ˆ ˙ ˝˛˙

�#����������������� 1 =#�' )*�� H2A + NaOH

M�����"�678 1 pH = 6.0

+&�=!(!�)+�-BC8,B>�),+-(01.+/

73

pH = 6.0

M�����"�678 2 pH = 11.9

Page 74: ˘ˇ - Chem ku-kpschem.flas.kps.ku.ac.th/SLIDE/SLIDE-53-TEACHER-ION... · 1. strong electrolyte ˘ˇ˘ˆ˙˝ ˛˚˜ !"#$%&'(˜ )*˚ HCl HNO HClO NaOH KOH NHCl NaCl ˘ˇ ˆ ˙ ˝˛˙

������� Calculate the pH at 0, 10, 90, 100 and 110 % titrant for the titration of 50.0 mL of 0.100 M HCl with 0.100 M NaOH .

At 0 %pH = - log 0.100 =1.00

74

AT 10 %5.0 mL NaOH is added.

We start with 0.100 M x 50.0 mL = 5.00 mmol H+

Page 75: ˘ˇ - Chem ku-kpschem.flas.kps.ku.ac.th/SLIDE/SLIDE-53-TEACHER-ION... · 1. strong electrolyte ˘ˇ˘ˆ˙˝ ˛˚˜ !"#$%&'(˜ )*˚ HCl HNO HClO NaOH KOH NHCl NaCl ˘ˇ ˆ ˙ ˝˛˙

Calculate the concentration of H+ after adding the NaOH :mmol H+ at start = 5.00 mmol H+

mmol OH-added = 0.100 M x 5.0 ml= 0.500 mmol OH-

75

= 0.500 mmol OH-

mmol H+ left = 4.50 mmol H+ in 55.0 mL.[H+] = 4.50 mmol / 55.0 mL = 0.0818 MpH = -log 0.0818 = 1.09

Page 76: ˘ˇ - Chem ku-kpschem.flas.kps.ku.ac.th/SLIDE/SLIDE-53-TEACHER-ION... · 1. strong electrolyte ˘ˇ˘ˆ˙˝ ˛˚˜ !"#$%&'(˜ )*˚ HCl HNO HClO NaOH KOH NHCl NaCl ˘ˇ ˆ ˙ ˝˛˙

At 90 %mmol H+ at start = 5.00 mmol H+

mmol OH- added = 0.100 M x 45.0 mL = 4.50 mmol OH-

mmol H+ left = 0.50 mmol H+ in 95.0 mL.[H+] = 0.00526 M

76

[H+] = 0.00526 MpH = -log 0.00526 = 2.28

At 100 %All the H+ has been reacted with OH-, and we have a 0.0500 M solution of NaCl. Therefore, the pH is 7.00.

Page 77: ˘ˇ - Chem ku-kpschem.flas.kps.ku.ac.th/SLIDE/SLIDE-53-TEACHER-ION... · 1. strong electrolyte ˘ˇ˘ˆ˙˝ ˛˚˜ !"#$%&'(˜ )*˚ HCl HNO HClO NaOH KOH NHCl NaCl ˘ˇ ˆ ˙ ˝˛˙

At 110 %We now have a solution consisting of NaCl and excess added NaOH.mmol OH- = 0.100 M x 5.00 mL

=0.50 mmol OH- in 105 mL[OH-] = 0.00476 M

77

[OH-] = 0.00476 MpOH = -log 0.00476 = 2.32pH = 11.68

Page 78: ˘ˇ - Chem ku-kpschem.flas.kps.ku.ac.th/SLIDE/SLIDE-53-TEACHER-ION... · 1. strong electrolyte ˘ˇ˘ˆ˙˝ ˛˚˜ !"#$%&'(˜ )*˚ HCl HNO HClO NaOH KOH NHCl NaCl ˘ˇ ˆ ˙ ˝˛˙

'��5�6-7���8-9/��(� )#$% :�;#;-)

)*�� AgCl, BaSO4, Ag2SO4

AgCl �9���&��'(�AgCl(s) Ag+(aq) + Cl-(aq)

][][ ClAg−+

78

Ksp= =��= 678l�="$��#�9������[Ag+] [Cl- ] = l�="$����� (ion product)

][][

][][

][][

][

][

ClAgK

ClAg

ClAg

sp

AgClK

AgClK

−+

−+

−+

=

=

=

Page 79: ˘ˇ - Chem ku-kpschem.flas.kps.ku.ac.th/SLIDE/SLIDE-53-TEACHER-ION... · 1. strong electrolyte ˘ˇ˘ˆ˙˝ ˛˚˜ !"#$%&'(˜ )*˚ HCl HNO HClO NaOH KOH NHCl NaCl ˘ˇ ˆ ˙ ˝˛˙

ion product <<<< Ksp ����#N)�Y���#�9�������7�Ion product = Ksp ����� (��#�9����Y8����)ion product >>>> Ksp )�Y��9���KL'�&���#�9���

���Y ;�Z#�) K =;�=����� ���������$�����

1%-*8D� (+8��!"#898&'3EF&=-G3G�'

79

���Y ;�Z#�) Ksp =;�=����� ���������$�����

��#�7=�� Ksp �8(� M9���9������ ���

��#�7=�� Ksp �" M9�9��������� I#H����9���������

Page 80: ˘ˇ - Chem ku-kpschem.flas.kps.ku.ac.th/SLIDE/SLIDE-53-TEACHER-ION... · 1. strong electrolyte ˘ˇ˘ˆ˙˝ ˛˚˜ !"#$%&'(˜ )*˚ HCl HNO HClO NaOH KOH NHCl NaCl ˘ˇ ˆ ˙ ˝˛˙

CaSO4 ���� �����"� > BaSO4

Ksp BaSO4 = 1.1x10-10

Ksp CaSO4 = 1.1x10-5

����������� ���������$�����

80

CaSO4 ���� �����"� > BaSO4

��8�=H� N��&���#�9����7 [Ba2+ ] = [Ca2+ ] )�H8�)�Y�SO4

2- M9)�Y��9���K� BaSO4 ���� ��9N��&*� [SO42-]

678)I��9��M9��� BaSO4 ���I��

Page 81: ˘ˇ - Chem ku-kpschem.flas.kps.ku.ac.th/SLIDE/SLIDE-53-TEACHER-ION... · 1. strong electrolyte ˘ˇ˘ˆ˙˝ ˛˚˜ !"#$%&'(˜ )*˚ HCl HNO HClO NaOH KOH NHCl NaCl ˘ˇ ˆ ˙ ˝˛˙

������� &���#�9����7 Cu2+ 1.0 ×××× 10-4 M l����! Pb2+ 2.0 ×××× 10 y3 M N��)�Y� I- M9)�Y��9��� CuI2 I#H� PbI2 ���� N�� Ksp K� CuI2 = 1.0 ×××× 10-12

K K� PbI = 8.0 ×××× 10-9

81

Ksp K� PbI2 = 8.0 ×××× 10-9

��9��� &*�=���)K��K��K� I- )6���# ML M96(�&I�)�Y��9���]��7

Page 82: ˘ˇ - Chem ku-kpschem.flas.kps.ku.ac.th/SLIDE/SLIDE-53-TEACHER-ION... · 1. strong electrolyte ˘ˇ˘ˆ˙˝ ˛˚˜ !"#$%&'(˜ )*˚ HCl HNO HClO NaOH KOH NHCl NaCl ˘ˇ ˆ ˙ ˝˛˙

H8D� =���3�/7% (Commom ion effect)

=H���#)O�78���O� 678)�Y�KL'�)�H8�)�Y������678�7��"�&�#9!! )*�� )�Y� NaCl &���#�9����Y8���� AgCl

AgCl(s) Ag+(aq) + Cl- (aq)NaCl(s) Na+(aq) + Cl- (aq)

82

[ Cl- ] )]Y8�KL'� [ Ag+ ] [ Cl- ] >>>> Ksp 6(�&I������)�H8��6� >���

[ Ag+ ] ��� M� [ Ag+ ] [ Cl- ] = Ksp

NaCl(s) Na+(aq) + Cl- (aq)������(��

Page 83: ˘ˇ - Chem ku-kpschem.flas.kps.ku.ac.th/SLIDE/SLIDE-53-TEACHER-ION... · 1. strong electrolyte ˘ˇ˘ˆ˙˝ ˛˚˜ !"#$%&'(˜ )*˚ HCl HNO HClO NaOH KOH NHCl NaCl ˘ˇ ˆ ˙ ˝˛˙

1%-*8D� =���3(L, MG�3(Complex ion equilibrium)

��#)�Y������)*Y >���*���&I���#678�9����'(������������#N�9�������7KL'� )*�� )�Y� NH3 &� ��#�9����Y8���� AgCl

AgCl(s) Ag+(aq) + Cl - (aq)

83

AgCl(s) Ag+(aq) + Cl - (aq)

Ag+(aq) + NH3 [ Ag (NH3 )2 ]+

Complex ion[ Ag+ ] ��� �����)�H8��6� K��AgCl(s) �9������KL'�

Page 84: ˘ˇ - Chem ku-kpschem.flas.kps.ku.ac.th/SLIDE/SLIDE-53-TEACHER-ION... · 1. strong electrolyte ˘ˇ˘ˆ˙˝ ˛˚˜ !"#$%&'(˜ )*˚ HCl HNO HClO NaOH KOH NHCl NaCl ˘ˇ ˆ ˙ ˝˛˙

������� �����)*Y >���

Ag+(aq.) + 2CN

- [ Ag (CN )2 ] -

Zn 2+ (aq.) + 4OH- [ Zn (OH )4 ] 2-

84

Zn 2+ (aq.) + 4OH- [ Zn (OH )4 ] 2-

[ Co(H2O)6 ] 2+

(aq.) + 4Cl- [CoCl4 ]

2-(aq.) + 6H2O