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C

• CH> HK (EO@@Q), TG, #

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C+; *; '(E@+'), G, K

C+; *; '(E@+'), G, K

>@@ H DJ@

H> HK @@ HH>@, G> <M HH I>@>>I >H@M @H > H @@K>< I@H>-H

IH>:

D@H G= -@ #OQ = -FEO@@Q

G: G** E?

TG > H < G> () <M MH TGR > H G> <M < MH I H >H>

(1 H, 298#). ' <M ><, TG H :

TG > H > > H <M HK HH IH. >H> TG > IH M LH@ H HH

< H >H> H H>. F L@ > E(H>JH> <M) K H > H H@MH H

>H> <M @I@ > I H > > HHI, H TG J@I KI@ > H .

E+: #; C !;;

ER@@ > H @HH>J (@ @@ @@ J@H< @@ HH>@) HK HK @-@@. <H H ER@@

H> H <H H >J>< @H HI< H MH, H @>@M H H> K>@@ (


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HI). ER@@ > I > J@H (). J@@ J@H< H @@ = H @-@@ HH>@ H IH> H> +

H @-@@ HH>@ H L>H> H>. >@>M,

EO@@Q = EOIH>Q + EOL>H>Q H<O1Q

EO@@Q = EOHQ + EOQ H<O2Q

HH>@ L>H> IH> (@ @H) > H <H>J H HH>@ IH> HH>@ (<>

@H). %H H@ @M H H IH> @-H>. H K, H H@ @M H H

IH> HH>@; > H > H H L>H> HH>@, >@M J H >< H H IH>

HH>@.

&H

>H>J IH> HH>@ IH> H> HI. J>K>< @@ IH> HH>@

H@, H >< H @@ > H H@, H >< HH>@ >H L>>N>< <H.

D+ *; E+ E+

ES @@ > H H HH @@ HH>@, K> HH H J@I K H> I H HH. H HH

>@I HH> 1 %@ (@ @>H) H> I 1. >>@ H H H HH @@ HH>@,

ES@@, H E@@ > H -H HH @@ HH>@, K> HH >H > H H> I HH> 1 %

I 1 H. HK @@M @H > H HH H H @@ HH>@ > I H @I@H H @@

HH>@ > M .

EO@@Q= EO@@Q -OQOFQ @; H<O3Q

'H >@>> H IH> HH K HM>@@M :

EO@@Q= EO@@Q -O0.0257QOQ @ ; H<O4Q

> H (@<O10Q) ( 10) >H H HI@ @<>H ( )

EO@@Q= EO@@Q - O0.0592QOQ @<O10Q; H<O5Q

BH IH> @> K H HHI > 25SC. DJ>H> 25SC I> H I H ><>@ IH>.EH>@@M, ES > E H H >H>

EL@ 1

H > H J@I E@@ H J@H> @@ @K:


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http://chemwiki.ucdavis.edu/Analytical_Chemistry/Electrochemistry/Redox_Chemistry/Standard_Reduction_Potential






HO()QPFO2+QO(0.1%)Q,FO3+QO(0.2%)QPPA<+O(0.1%)QPA<O()Q

#L%$IN

I H &H IH>, K H H@> (EO@@Q) H H> H K> H @@ >< HH

H H H> IH>H () J@. ' K J H> H H &H IH>, K >H

H HH> H >.

@J:

EO@@Q = EOHQ- EOQ

= EA</A< - E

F3+/F2+

= 0.800-0.771 = 0.029

&K H H> E@@ H H>

F2+(0.1%) + A<+(1.0%) V F3+(0.20%) + A<()

H &H IH>

E@@= 0.029 -(0.0592/1)@< F3+/F2+A<

=0.029 - 0.0592*@< 0.2/0.1*1.0

=0.011

K: $ E<*< C;;

(#) > H I>@>>I HH <@ H>

A + B @H><H C + D H<O6Q

> L M H H> IH>H:

#= OCDQOABQ H<O7Q

EL@ 2

G>J (# = 2.81 H> 10O-16Q) @@K>< H>

CIO2+QO()Q + A<O()Q ><H@H CIO()Q + 2A<+


License. 4

http://chemwiki.ucdavis.edu/Analytical_Chemistry/Electrochemistry/Nernst_Equation

http://chemwiki.ucdavis.edu/Analytical_Chemistry/Electrochemistry/Nernst_Equation



F> TG.

#<;:

H @@K>< I@: G=-"$K

= 8.314 L 298 L @(2.81L10

-16

) = -8.87L10

5

= 8.871 J

$ "; B; ; $

@H>> HK TG, #, ER @@ H M H @@K>< ><.

K

• R = 8.314 J mol C-1

• T = Temp in K

• n = moles of e

-

from balanced redox reaction• F = Faraday's constant = 96,485 C/mol

ER@@ @I@H I>< H @@K>< I@:

EO@@Q = EOHQ U EOQ = EOIH>Q U EO'L>H>Q H<O8Q

EL@ 2: % G=-"$K

IH> F> H ER @@ H @@K>< I@ @-H>

#L%$IN

1. DH> H H > H H>

() W 2+() + 2- A, 'L>H> (> () > L>H> HH 0 H +2)


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CI2+() + 2- W CI() CH, IH> (> CI2+

() L>H> HH +2 H 0)

2. DH> H ER @@ J@I I>< H H IH> HH>@ H@ (@ 1)

() W 2+() + 2- -0.763

CI2+() + 2- W CI() +0.340

3. E + = E+; - E

= 0.340 - (-0.763)

= 1.103

EL@ 3: >< TG=-FER@@

F> TG H @@K>< H>:

2A@O()Q +3BO2(@)Q ><H@H 2A@O3+QO(, 1%)Q + 6B-O(, 1%)Q

#<;:

#; 1: H H H> >H >H HK @ H>

2A@O()Q ><H@H 2A@O3+QO()Q

3BO2(@)Q ><H@H 6B-O(, 1%)Q

#; 2: B@ H @ IH> I>< ', , < I>< -

2A@() W 2A@3+() +6-

6- + 3B 2(@) W 6B -()

#; 3: F H @ @ H>, K @I H I @ - I @H > H @I@H> TG.

DH> H ER J@I I>< H H IH> HH>@, I>< H ER @@ H@.

2A@2() W A@3+() +6- -1.676

3B 2(@) + 6- W 6B -() +1.065

#; 4: DH> E+ = E+; - E.

= 1.065 - (-1.676)


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http://chemwiki.ucdavis.edu/Reference/Reference_Tables/Electrochemistry_Tables/P1%3A_Standard_Reduction_Potentials_by_Element

http://chemwiki.ucdavis.edu/Reference/Reference_Tables/Electrochemistry_Tables/P1%3A_Standard_Reduction_Potentials_by_Element



= 2.741 &

#; 5: ' ER @@ @I@H H I @ @H J H>, K I G = -FE+

= (-6 @ -)(96458 C/@ -)(2.741 )

= -1586"

> IH> I H @I@H ER @@ <>J # # <>J ER@@. =298 #, H > HH H H @@K><

IH> I: E+= (0.025693&/) K

EL@ 4: >< ER @@=(/F) @#

G>J H ER @@ H H>

CIO()Q + 2+O()Q ><H@H CIO2+QO()Q +O2(<)Q

> -0.34, > H I>@>>I HH (#) H H>.

#L%$IN

#; 1: @>H >H HK @ H>

CI() W CI2+()

2+()W 2(<)

#; 2: B@ H @ H> K>H < H H>

CI() W CI2+() + 2-

2+() +2- W 2(<)

$ =2

#; 3: F H L@ J, ER @@ = -0.34

-0.34 = (0.025693/2) @#

# = (-0.34 L 2/0.025693)

K = 3.19 > 10-12

EL@ 5: H>HM


License. 7



G>J H @@K>< H> H> TG, #, E@@ H @@K>< H> H H >H>? H> H>

HI?

%O2+QO()Q + #O()Q ><H@H %'O2()Q + #O()Q

#L%$IN

#; 1: H @ H @ H>. $@ K> > IH> K> > L>H>. F> H

>< ER J@I H @ H>.

%'2() + 4+() + 2 W -%2+

() + 22'(@) IH> +1.23

# +() + - W # () 'L>H> -2.92

#; 2: >H H @ H> > >> @IH>, H> H ER @@.

ER @@ = ERH- ER = +1.23 - (-2.92) = 4.15

%2+() + 2# +() + 22'(@) W %'2() + 4+

() + # () ER @@ = 4.15

#; 3: F> TG H H>.

TG = -FER@@

= -2 @ - L 96458 C L 4.15 = -800.60"

, > E@@ > >H>J TG > <H>J, H> H> > HI.

#<? $*

Eo cell $\Delta G$Q & K

Relationship

Reaction

Direction

Spontaneity (as

written)

>0 - Q<K Forward Spontaneous

<0 + Q>K Backward Non-spontaneous

=0 =0 Q=K No Reaction N/A

!*

1. Find E° cell for $2Br^-_{(aq)} + I_{2(s)} \rightleftharpoons Br_{2(s)} + 2I^-+{(aq)}$


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2. Find E° for $Sn_{(s)} \rightleftharpoons Sn {̂2+}_{(aq)} + 2e^-$

3. Find E° cell for $Zn_{(s)} | Zn^{2+}_{(aq)} || Cr {̂3+}_{(aq)}, Cr {̂2+}_{(aq)}$

( K M @IH>)

• If the E° values of the reaction is negative, then the reaction is NOT spontaneous and therefore the reverse reaction

is occurring and the electrons are flowing in the opposite direction.

• These values are tabulated in the standard reduction potential table.

4. F> TG H @@K>< > @ H>:

F2(<) + 2- W 2F-

()

$>+() + - W $>()

5. F> H I>@>>I HH (#) H @@K>< H>: ( Hint: F> ERC@@ >H!)

() + 2+() W 2+

() + 2(<)

6. F> ERC@@ H <>J H> H H >H>:

CI+() + - W CI()

2() + 2- W 2-()

( K M @IH>)

A1. +0.530 V

2. +0.137 V

3. +0.339 V

4. +1139.68 kJ

5. 6.4 x 1025

6. +0.195 V

"+1. Brady, James E., Holum, John R. “Chemistry: The Study of Matter and Its Changes”, John Wiley & Sons Inc 1993

2. Brown, Theodore L., LeMay, H. Eugene Jr. “Chemistry: The Central Science” Third Edition, Prentice-Hall, Inc.

Englewood Cliffs, N.J. 07632 1985

3. Brown, Theodore L., LeMay, H. Eugene Jr., Bursten, Bruce E. “Chemistry: The Central Science” Fifth Edition,

Prentice-Hall, Inc. Englewood Cliffs, N.J. 07632 1991


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4. Gesser, Hyman D. “ Descriptive Principles of Chemistry”, C.V. Mosby Company 1974

5. Harwood, William, Herring, Geoffrey, Madura, Jeffry, and Petrucci, Ralph, General Chemistry: Principles and

Modern Applications, Ninth Edition, Upper Saddle River,New Jersey, Pearson Prentice Hall, 2007.

C;*<;

• Deborah S. Gho, Shamsher Singh


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chemwiki book 30 dec 2015

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