~~Q;Ci~ .~~

qq 7 ',Wo (1) ~ 1999 Tl 14-2 1

~-qlf8ciSlq:;l~lRtfl ~ ~ C!fCf)I~tfl ~ ~ 311cffi1tfl{trT ett~lm~RCfl

~~ lFi f*;~IMfq fcrm ~ ~ >fCfiT:/T'

~ m'lWT, ~ . t:;.r. eft. m~ClfCl€Ol 1 111:l, ~'tlT 342005

mB : 9 ~ 1998; ~ : 30 1Wf 1999

. ~ ~p ~ ~ ~ >:;. ( ;. ~r-r ~ " ~ ~ ~ =-nrr mn~T - 5 15 c()1 'i10 Icsl4JI {:th Ii{Cf) \31"lVf H3PA) ~1 ~WlIIC1Cf) \31"lVf (AA) CllT 0l 1CR11Cf)(0 1 ~~x l "l " co 1'11~<.l Cl I\i ICl (o l

it, HCI04 l1Tur:! (0,02 B 0.20 mol dm-3

), ~ ~ (NaCI04; 0.5 mol dm-3

) IR >r~~ CllT % ~ ,~ CllT HHPflCf) (lJ lfilJ II:l ~ 1:2 % I ~ cfi'r rllir [H+] it % ~ m~ tTGffi %, ~ ~ ~ it % ~ m~ ~ %, Q;Ci %fcm ~ ~ \3f:!I:ffi Gl(i[ ~ B Cf)lf (0.80) 0lTill % I >r 141fTlCf) ~ ~ 0lT'tIT\

IR fffim~fu;r Wr~ltvl H2A, HA- Q;Ci H2PA-~ cfi'r TTt ~ Jffi iM ~ 2k12 = k1 + k2 Ka[H\ 1 RtTIftl P+-rr. ~ ':1,- -2 . 2 3 ·1 ·1 .;>,.:>. , . RI ~ ~ " Ic()<.ll 'Tm (> I k1 ~ k2 C() 25°C IR ~ ~~T: 1.5 x 10 cr 3.15 x iO dm mol s >rIR <:, 1(1 tt I jtiC:(lq IMI \31"lVf

H3PA &TIT AA ~ 011CR11Cf) (01 it, H3PA ~ ~ (Keggin) ~ it J QR4Cf M006 ~ ~ Mo(VI) ~

'3'NClfltc:f ~~, cr ~ P(V) ~ ~<:1 ~ % I ~ ~ [Co(III )W1 2040t &TIT AA ~ 01ICRilCf) (o l

B ~ %, ~ ~ 't.ffij 0JT<:R Co(II I) Jrerqm tn "fT\11 % I 'f~, ~ Q;Ci ~ ~ ~ ~ ~ k1 • ' ~T 1/ 1/ ·1 II 1/ ·1 ·1 .

~q k2 co II'I ,!; ~~l: C. Hk1 = 101 cr C. Hk2 = 17 k J mol ; 6 Sk1 = 60 cr 6 S k2 = ·140 J mol K ~

,\Gk1 1/ = 83 cr 6 G k2 II = 59 k J mol' 1 ~ I k2 q~ ~ ~ ~ 6 Sft Q;Ci ,:#r~wpl Cf)lf 6 H ft, HA- cfi'r 0lT1rC!J

~r~fmctl C!lT ,~ C!J7:ill % I

JffiWRT

QWT t'r if @ or mfum1 ~ ~ 1j1~ c.sl 4JIf41)IRCh

~ (H3PMo1 20 40. 29 H20 , H3PA) ctr lJ;Gfl q~

~ ~ ffl if Blfrm ~ % I H3PA lJ;Gfl ~ ~ %, ~ ~ ::rrr or -31 1 CR:fl Ch ( 0 I ~ cfi'r ~11fill ~ CflT\UT

~ 0fldlfTlCh ti~~ if IjIMICF{M( (molecu lar) \:,~

~ ffl if m Fcnm \JfTW %, ern ~~ 1972 if ~ ~ ~~f G-l\igi'IJ11 if 2·~ Chl f.:r:rfuT2, ~~ 1~1M'11 Chl

~~I~ I ~iftCh ~ if -31 ICR:flCh (O I3 or ~~ Chl

41 1;j)~RCh ~3!Wr if q§,M"ICh (O I4, 3TTfu. I H3PA ~ ~ "\ r- • 5 ...J:+ " ~ ~ "\' f".

~ ~ C(JI ~ -gr C' , 1'-'1 (1C(J ~ ~,

[PM01 20 40)3-, if 4 -31ICRit)IJ1 1 ~ ~ 00 ~ Chl ~~ CRffi ~ I 12 funrt cnB or 24 ~~ 0l ICR:flJ1.-f ~ ~ 1j1~c:%11j (molybdenum)

~0lT ~ 12 ~ q.ffi; ~ I H3PA Chl 2o ll ~Ch

m~~ ~ ~FhlmCh ~ &m ~4 if >rrR

mC:(1 4IMI ~ M tr Fcnm J1l wmrr % I ~(q) l mCh ~ [(ascorbic acid) (AA)) Chl 0l ICR:flCh(OI

~ ~ &m q \31WT-01WT ~ if Fcnm G1T

~ % I ~ -q~ ~ ~ V(V)6 ~ m~

~r if ~ Fcnm TTm, FJru-ii ftsTCR:r ~ if ~(q)I4C: Wc:f) Cf1ill %, ;r Fct 2-~ I~ICf?11 ~ ~-tl H h"H 0 1 if $ 1 ~ch'!c:11 CfldT % I ~ ~MCh Chl CA1T Jffi '1.fr ~ ~0lT ern ~("I)-EDTA ~7 q

:\ .... -" .... 8 (' '-' f<'" .... ... ~ ~CfJWWFlIQ)(co COT ~F.fJl ClCfl ~ 1J ',jjl'il~/..II ~

lJ 6!:lINIi S'31T % I 1::% '~ m 9 if ~J,q:)IFciCfl ~ it f?:T-(1 , 10 -~~) ·31faB(III) illU ·31ICf'1.1ICfl(OI chl

., ' ~10 ~ r ...l+-.--h ~, llTCfiT.f 1'1 r.~ 1 '\l COT Ij 'i /..II' I CfJ1: , 'Tffi \3YJIT 'i 1 ~ q (1 '1

IIT'l chl ~ I m ·31ICf'l.1ICflII chi chl 9fHI~Cfl fui<n~l'rffifT it 31T'C:lTI qT %fcm 11 2r ~ fu.<:n fcn ~~q:)IFciCfl ~ COT

~~fc®

~3lf~ q ~ 1flfr 01f~ ~ nw:R

fcr~Mqoll~CfJ W- ~ ~ , cPU 1fIfr ~ fu~ \1Wl

if Cf1Tif rm I H3PA (BOH) r.h'r \1Wl 7) ~'if*,J,<: ~;j)Cfl(OI it qQ~ CaCI2 q.: ~ if f'i A~;\h!5 1i ~ ~ Fcfl<:rr Tf[ff I H3PA ~ ~ r.h'r ;:fT;f-31qr:)IQCfl 7) .~

"'\ ~ .... .... "'\ p-, CfJTCfJ , ',11 ~ q, ~ (ee rie sulphate) q Q)1""GWiIi·FFl

~ fr q~iq JfTWT'i" IIT'l ~Hch10 1i Fcfl<:rr Tf[ff I (::!; '"' ., ~ f ,, ~ '"'

rrCl,'=:ch:T\ljq~Cfl 'JrvT COT ~ 'lGCl 01 1 Cfn J1 'i TT&f 1 &~

JWf if (fRIT CAT Cf)T , 3"41WT if ~ Tfm ~ ~ ~ l1RCfJ ,~ ~ 7) TWf ~ ctr ~ qfi?..ffi; if

R ~ r

31,!~I'11i CfJT ~ COT ~ I

~~

·31f1ifulm N.!!lUT H3PA, HCI04 ~ NaCI04 rhl f.'mcl "'lftT ~ Cf1TITI Tf[ff ~ ~ ill1l ~ (H aa ke 0 8

G) if ffiCf)T ~ ill1l-"lJfRllT{ ~ rrTI, ~ ~ ± 0.1 "C m I ~ ~J,q:)IRiCfl ~ it ~ r.h'r ~ fui<n >TWl1 rtf ~ I .3lf~ chl ~ r.h'r , ~ H3PA chl ~ if ~ ifJ' m~, 650 nm IT{ AIMIL

Speetroehem MK II J,.qCfS;P:hliliflco( IT{ , 'JfCf~~ if ~ it m~ ~ Fcfl<:rr Tf[ff I um ~ q \31T1ffift ~~ CFilR ctr J1f~ ~ ~ 0lTCf~"[lCf) qftR~ nsft ~ -;pJ fcn Q,%IFciCfl ~ chl7JT'"'%fT H3PA rhl ~ fr

-..~ " r- r- "'\ "\ '\ ~

~ TIT \.J11 <lCfJ \@l ~ I Tf'4T!:T<WT 'i I ~ ~1'J1 'i CfJ I '11'f-n /..I

CllliICl(OI q ~ ~ q .~ N.!!lUT if ~ ~ ~ 0.5 mol dm·3 NaCI04 chl ~ fr f.r:rI1' ctt ~ I ~ ~ ~ Cfl0 it ~ m 3lWT-'3lWT \iltfIlR

qT~~1

~~ " " fi1 " ' h . .J11'i1~/..I1 COT (H H~ICfl ( OI iii ~ CfJB (>~, H3PA ~

AA it ~-3lWT '~ ~ ~ N.!!lUT m rrQ I

40°C IT{ N2 ~ CllliICl ( OI q 48 tR .~ m it CllG: .31f~ it '3l'"n if em ~ H3PA m AA 0l~ ~

chl ~ ~ ctr rrfr I ~ ~ if [A A] : L\ [H3PA]

COT ~ 2 : 1 mB S31T I

H3PMo1 20 40 + 2 C6HS0 6 -7

H7PMo1 20 40 + 2 C6H60 6

... (1 )

.3lf~ fif.!!lUT if ~ .31f'l1CflTl:CfiT if 1 m L

Q}hl~M1'iI~~I~ ~'1 ~ 30 flRG N2 ~ chl TT4T, rnq~~ ~ it fuw:RT r.h'r ~ 31f~ ~q chl TT4T ~ 31f~ N.!!lUT, .~ ctr q:uhn it ffi1! N2 it ~ c1l\iICl (OI if nm Tfm I WfIi'T 20-22

tR q~~ qIMI Cl}hl ~ ~'1I'iI~~I ~C'1 COT ~iro '31cl~"-M" mB S31T,

m STf Cffi1 COT ~ % fu; H C 104 llTt:lfl1 if H3P A illU

AA ~ 31ICfl.1ICflIIJI if TFf ~ ~ ~ % I

qftuwl ~ arr&lT

(i) kobs qfj [H3PA) Iff frJfrrrr

~ ~ CfiTTC8 chl ~.9-R ~ rn'i'r ~, H3PA chl ~ r.h'r ~ TIT ~ qRClf~1i Cfl0 q.: '1fT kobs COT '1R

fTw {Q\i1 %, ~ ~ iTm ~ , fcn H3PA qT kobs

chl f.r'o/m ~~ CFilR ctr % I (TfTTl1fr 1)

(ii) kobs qfj [AA} Iff ftrifrrtr

~ f.r!:fTcn 3TWT-'3lWT ~ if AA rtf mnrllCfl 7JT'"'%fT qf( Cl f~1i Cf)T q ,~ ~ ~ r.h'r P:m T@' ~

chl TT4T I J:fIirriT it iffiurrlf ("ffi(TJ\T 2) fr ~ l 'i Cfl ~'1 Ii I

%, ful kobs ~ '1R q AA chl mW% ~ ~ m~ '31ljQlhlCfl ~ \3lT\iT % I kobs q [AA] it -qUi m'l?

mruft 1 - kobs ctT mfi'qq; [H3PA] qT ~, 40± · C qT

3 ·3 + ·3 10 [AA] = 1.0 mol dm ,[H ] = 0.1 mol dm ,

[ I ] = 0.5 mol dm

104[ H]PA]

(mole dm-3 )

1.0

2.0

4.0

6.0

S.O

10.0

·3

:irTcT 104 kobs= 1.1740± 0.05 ~-1

(5" )

1.12

1.26

1.22

1.11

1.13

1.21

16

~ 2 - kobs qi'r ~ [AA] q-{ f.rit@. 40 °C q-{ 4 ·3 -3 + ·3

10 [ H3PA] = 1.0 mol dm . [ I ] = 0.5 mol dm . [H ] = 0.1 mol dm

103[AAI 104

kobs k1 2

(mol dm·3) (S,' ) dm mar l S·,

1.0 1.11 01 11

2.0 1.74 0.082

4.0 3.18 0.080

6.0 4.92 0.082

8.0 6.42 0.080

10.0 7.91 0.079

20.0 15.73 0.079

• ·3 -1-1 \3WJ(f k 12 = 0.085 ± 0.006 dm mol s

" .

"

/

-j ?

" ,.

,, -v, ,. ,I, ; Z. 11 2 .\ I 2 ItI

I + I OI~ 1 .. \ .\1 IO:' l,IAII<Ii)i1 ~.,)

I

'"

~ 1 (q) - log k obs q log [AA] ~ 1Wl Bl<Rl

(fu?r 1 (0l)) ~ en: ~ mm WIT, ~ ~ it ~ ~ >ITR M ~ I ~ kobs ctr AA en: >J~ W ctr ~ G::1TRfT ~ I ~ k1 2 (= kobsl[AA)) ~ f.lP-mf qftlrrur u '4T {If£llfq("j ~ ~ I ~ log kobs ~ log [AA] ~ lfUl ~ ~ ~ ~(slope) €r '4T Blffmf ~ (fu?r 1 (q) ) I

m~-m:Q tRill ~ I [H+r 1 q Kobs ~ lfUl (fu?r 2) it urm WIT >ITR tnm %, vft Y-01~ en: 3R1: cis ~ % I

(iii) kobs qff [H+] W f.tifrrrr

[H3PA). ~{q")I~co ~ ~ ~ ~ coT ~ ~. qn ~ <:rm 25. 30, 35 q 40°C en: H+ ctr ~ 0.02 U 0.20 mol dm- 3 qf{qf('i("j ~ [H+] en: kobs rtf f.t~ ~ ctr lJ1fr I w:WTI ~ qftuw{ (~ 3) €r ~ ~ ~, fct kobs COT llR [H+] ~ .~ ~

k + ·1

12 = a + b [H ] ... (2)

~ a q bCOT llR ~ ~ fG1c u ~ M rrm. vft fct ~ 4 it ~ ~ ~ I

(iv) o3I1<lf.tIi rrRrffT W kobs qff f.tifrrrr

~ ~ en: Kobs ctr ~ ~ coB ~ ~. [H+] = 0.05 mol dm-3, [H3PA] = 1.0 x 10.4 q [AA) = 4

x 10.3 mol dm-3 , (1N'fR 40°C q ~ [NaCI04] en: kobs COT lfR ~ M rrml >ITR qftuw:IT U ~ ~

; .:i

Tcr'llT ~ ~ ~!IT: " " ~fi" ~ "ft STScllT -Ij I~ e.g Plil t'~rco .~ if CJ:Ff)Irc1co .~ CllT '311<R11coPJI 17

~ 3 - kObs ctT lffifi''qCf) [H+] Il\ f.r~ 4 -3 -3 3

10 [H3PA] = 1.0 mol dm , [ I ] = 0.5 mol dm , 10 [AA] = 4.0 mol dm -3

[H+ ] (fl'q'll'R (0C)

mol dm·3 25 30 35 40

11 ,11 '

kObS 104(~ 1 )

0.02 3.2 4.20 6.2 7.7

0.03 2.3 3.00 4.5 5.8

0.04 1.8 2.40 3.7 4.9

0.05 1.5 2.07 3.4 4.3

0.075 1.0 1.50 2.6 3.5

0.10 0.86 1.30 2.2 3.2

0.15 0.73 1.00 2.0 2.8

0.20 0.60 0.90 1.8 2.6

~4-~ a q b~lfR

25

a )( 106 5.86

b x 105 302

I II ! n .h l

r- + -1 *\

rt.r:.l 2 - kobs Cl [H J co 'lUI' wq..q

(fl'q'll'R (e C)

30 35 40

7.39 9.73 11 .32

5.23 13.06 20.43

log kobs = log kobs + 2 A Za Zb ~I / (1 + ~/) ... (3)

. ~~~ P-.-..,.....,.. ~ ~ A I "'Y I~ I'1Y\lIC{) Q 1~~1c{)1 'l1f.1 25"C q{ 0.54 (>, Za

Cl Zb .~ ~~~ q{ ~~T ~ I (tffiUfr 5, ~ 3)

(v)~ ~ Wkobs W.fl'J1TcT

.~ ~ FffiLl IChI (Chi' c#r ~ ff'm ~ ~ ~ ~ if ~, NaCI04 ~ P-lR q{ LiCI04 B- coB q{ , kobs ~ 'l1f.1 if ~ Cfi1ft ~ rrm, ~ Li+ c#r em ~ B- w:qf.-t«1 M \ifT ~ ~ (tffiUfr 5) I

(vi) ~ {H3PA} qff rrRTrTT W kobs qff ~

.~ q{ ~ ~ [H3PA] c#r lfffi COT

~ ~ M rp:rr I ~ H3PA c#r lfffi if 1.00

x 10-5 B- 10 x 10-5 mol dm-3 ~ coG q{ kobs COT

'l1f.1 ~ qr:rr rp:rr , ~ ~ ir<=rr %, FcB ~ (il CfS!11

~111"d(OI COT ~ \3\#l 'lOnLl ~ ~ (tffiUfr 6) I

~. FcB ~ ~ ~ ~ m~ kobs COT 'l1f.1 '1ft Cf(pffi ~ ~ .:;..p.,..,.,.13 " " ~ ~ -=+.,..,.,. ~ Q I -'5lq~1 J.PH.Ch(OI co ~ "11 ~ V">j1 COT Iq~('1~VI C{)~'1 .... 'l1P1c.%'1'l CC1 AA c#r H3PA q{ ~ B- CRill ~ I

qr log kobo, ~ ,111 (1 + ,11 ) ~ 1l'CIT 3l' f1ll if 'C% m~ H3PA CllT .~ ~ ~ I 'l1P1ii%'1'l CC1 H3PA if 1m ~ ~, vir Y-31ef q{ 3lcl: @U5 ~ ~, ;Jfi log ~~ m ~41"1ChC11 qffi 12 'lifAco%'1'l \3lT<Rl if B-~ kobs ~ quq{ ~ I 'llfMco%'1'l \3lT<Rl ~ qfq ~ Mo \3lT<Rl if ~ ~

18

lJT7ll1T 5 - kobs ctr ~ ~ IR f.rifror .40' C IV 4 -3 + - 3 3 -3 10 [ H3PA] = 1.0 mol drr; ,[H ] = 0.05 mol drn ,10 [AA] = 4.0 mol drn

[I] liCIOJ NaCI04

mol drn·3

0.15

0. 10

0.20

0.30

0.40

0.50

~:;rrq:) COT im'f

"TJ7lliT 6 - kobs ctr 31qqfu-rr [H3PA] IV F-PMn, 40°C IR 4 -3 -3 3

10 [H3PA] = 1 0 mol drn . [ I ] = 0.5 m ol drn , 10 [AA] = 4.0 -3 + -3

mol dm ,[H ] = 0 1 mol drn

0. 10

0. 20

0.40

0.60

0.80

1.00 -' 4 .' -1

31T'l\1 10k obs = 3.19 ± 0.025 'l'{)1JS

keos " 104

(~-1 )

3.20

3. 18

3.15

3.25

3.27

3. 18

4( -1 kobs '" C 10 1JqjUS )

2.52 2.62

2.87 2.95

3.15 3.30

3.48 3.61

3.65 3.87

3.80 4.21

0.76 0.80

'j ,1

'"

-----------------

Cfwl 13:1 {<\4 ~ ~ % 14 I 1 R {.q Cf?l fil <11 iT R~ ,,<;. QT ~

%, Fcf; ~ c8 fitm q YIFvlc:% <iY iT ~ 01TdzHi~lV11 '31ICf{fl\iH ~JTI q iT Fctm ~ 011Cf{il'iH q~ C{il

!'llil;:\'ICfJ ( OI 15 it \Jffi1T % ('I'm ~ H3PA ~ ~ if '31Tt:rCfJ(1ll qn: \3ITGl1' ,~ QT m % 16,1 7, ~

~ q H3PA ~ q fcmr2T Mo(VI ) ~ .~ v, r !"' ~h ~ m, m 01 4'tlIi:lCfJ C{il ~ 1R 1"'1 ~ CfJ1(lT Q I

H3PM o12 0 40 + 2e- + 2H+ --7 H5PM0 12 040 ... (4)

H5PM o12 0 40 + 2e- + 2H+ --7 1-17PM01 2 0 40 ... (5)

[H3PA] r ,~ ~ Mo(V) \3ITGl1' ~ \~!(fU;T

~ ~, \31(1 ; it JffilRr iT 01 ICf{i lC[ld ~ g1: [H3PA] if qGrif ~ ~ [Mo(V) --7 Mo( VI )]I 95% if ~ 1OIIfMc.%'iY

11 . .1

~ 3- 109 kobs q ..) , / ( 1 + ~, ) ~ "fur ~tl

~ 1 ~$) 01'i 46Cf{il~s [H3PA]r CfiT W(§ ~ r{ 01 1Cf{flC[ld

CfJ\ ~ %17 I

H3PA ~31 ICf{fICfJ (O I ~ ctr &<:rrfclftt ~ rn -, ~ " y ~ ':i1 -, 2 18 C'G( 14I Ml 0w:RT \JH1 G'InChlCllv G(III ) .~ ,

~m=tc (I V) \3ITGl1'1 9 ~ '?r 01Wl.' % I H3PA ~ ~~ ~"" rn -, ~" ~~ ~ +--,p,...". ~ 01 1 0 1 ~ qO ~1'11 QG( 141C'11 01 1~"1 >j ctl'>il ~ IQc\ 1 ~,

~ f.'r;f '31lcru"ICfJ (O I ~ if ~ QT \Jffi1T %,

~ H3PA if ~ \%Gf141Jl ~ 4i 1 {~( {i

~ n;m %5,21 I ~ c@' ~ Fc@Tt:rill c@'

C2:fT@T P(V) / P (III) [P = - 0.20 V) ~ Mo(VI) / Mo(V)

q1 7 [H3PA] r ,~ ClT4' Il\ 4 'tfUZ if ClIg)yosM'li:l 0 2 iT [P = - 0.41 V) ~ ~ 01 1Cf{fICfJ( UT ~ ~ \31Tt.n\ 1R

011 Cf{-n C[ld ~ Tf: H3P A if CRcrr \Jffi1T %, ~ ~ ~ c@' \JfT wmft % I

'" ~ q:i' ~ 18(ii i) , ~ ~ ;>; GIl liqlcr 2(111) &m AA en .3-1 ICRlCfl{Ol '1

mom AA, 2>IIRlchlql(,2G t WOG ctr \3iPOCfJMchILl

~ If W(VI) ~ c@ W(V) q .:wr-cITtl(f C{){ ~ ~

~ fch Co(llI) ~ UTi'! .m<:R illU g1: W (VI) if ~ If '311cffiJ1id it \Jffiff % ~ Co(III) ! Co(lI) q;r n.~lcp.i - -., ;::"OT.:T -100 I' ~ I v : Iq.,y ., J (> ,

5- - slow [Co(III)WI 2040] + HA --7

(VI V 6- •

[CO III) W l1W 0 1\ 0] + HA .. . (6)

[Co(llI) WVll1WV 040]6. ~ [CO(II )W~~ 040]6-

.. . (7)

tfiR ~. TRf fit'? () ql(l1 \3W-RT if ~ tng

o3WR' Co(lll) <:IT ~ Jltng o3WR' P(V), 12W06 m M006, [Co(III)W q H3PA] c8 \3i2 tf,('lcnILl ~ ., ~ tlm \Q(f[ %, qct ~ EM I Cfl I (ch j }Tzrc:rr f ckll iOl co

t ~\3iT t mil ~ if;iff JlT 'WIT, ·31(f : ~ql-=iICflI('lI crG

(III) it Co(lll) tnT ~ W06 ~lITD tr ~ iT 'WIT % I Co(III)W / Co(II)W Tlf if ~rsj.l ~ c8 ~ ~-=+. Fcf ' ~ "-' 15 ~ YIY q q'lI' '1 Cfl3 GIl 1('f)"H illU c:nr ~ I

~~fuJ~fh~

~t~c:nr H+ c8~t~~Bl::Tcw-n wa11\T C{){(fT %, frt ·31fAfulm H+ ir qjftA iEfT ~ , ~~~~

H1PA <TI AA m -iH' j i:tJ '~W:l;j'r.h(OI 'lJI-<if fr ~1 If[ ~ . ~ ~ I ;:rffim ~ if H3PA ~ f.~ i ldl

t Wc.n.:r HCI04 ~ WWf 01'Vf c€r ~~~ if HPA2-

3 ~ , ,.., " , "' 21-23 " q PA' - ~'-tl tnT $l12111Cfl(OI ~ ;:;:rrm ~ I ~ ~ fcnrr<:R If f.l h11~11@ (1 ~ tfR ~ f:

H3PA~ H2PA + H+

H2PA-~ HPA2- + H+

HPA2-~ PA3-+ H+ -....,..

... (8)

... (9)

... (10)

Kl , K2 q K3 ~ R..9~ tnT 1lR mer ~ m I H3PA

q H C104 ctr ~ B'T'1m Wfl1lT wen- 111~ ll1fT %24,

\310: Kl tnT lff1 ~ llR1 \J1T %ill ~ I ~f\'fm Fc:fwR If H3PA TTf ~ irTr qct H2PA- ~q if mW-ffi \PIT I fuill<:l q -~ fq~ R~ K2 lTil K3 q)f '1R

m ~~TWfT If ~ctT ~ ~ ~ ~ fc8:rr %, ;Jfr~~T : O.12±0.005qO.00023± 0.00005moldm-3

'CJl<'lT lJ<:ff t I wirrTI c8 [H+] $ ~ ~ HifICfl(OI (10) ~....4+~ ~ +

~ 'j'-t~I'1I "1(i! ~ . -~-wco ~ H ~ ':V, ~

'iJilI. (10) $ '3TjBR [PA::'- ] ~ >fR1 ~ w.nrfr t i H+

~ tnT CTTtrCfl >NTCT ~ trlT. (9) ~ n~n:n :m ncm=rr

%, q H3PA t fihQICflln ~ H2PA q HPA2. -qR \ill

~~I H2A K[I HA- + H+ (Ka = 0.93 x 10.5 )25 . .. (11)

~ (11) $ ~ AA ctr ~ UbLlICflI{l Wl~lrn iT '.iq") ~1 f; i ~ JlT'~ If AA ctt ~ ~ Wl~lrn 'IWT #rill f; I <W!: ~ H2A cit tt UbLlICflI{l Wl~TFn l{Rf

\JfTir ('fq .31f'l1fui<:rr if ~ ~ qi"{Cid'i m q-{

.31ft! l?h q I c8 TTfu If ~ 1ti i8T ~ ~ SIfI'llfTICfl

qftuwfi 7.0 '31Tffi .~ ~ ~ q-{ ~ tnT

~ cWr WTdT %, Jl(f: HA- fihm~furr Wl~lrn 1lRt ~ ~ I .%RW I3 ~. t ~ UbLlICflI{l Wl~fm WfR

~~T ~ il11 ~ I log kobs $.,j[ I( 1 +.,j[ )~ If'CIl' ~ 3, CflT ~ %fcm fI-T'ICfl(OI t ~ ~ -ij Cf)'q

(0.80) .3iTill i', .Jl(f : UbLlICfllfi W:r~fr\1f ~ ~~T qrffi qct ~I\T 'l{r ~ ~ q H2PA', H2A q HA' CflT

I~QICfll i l ffllfRT lJ<:ff t '1'frt HPA2-cit I AA if ;:r~ citfZ ctr f.nfun, H+ tnT ~tTq) >rmcr, ~ nR'ill tnT m >NTCT, ~ tnT

~ ~" ~ ~~ nHPiICfl(UII'1ctILl ~ (2 :1) q ~ ~1{>1~'>l1 C!>«hIii'i.iCfl

01'Vf .:mfu ~"rfTTCfl qftuwfi cit CflTlf If M ~, ~ ~ 7.0 ~ f.lh1Af@d, BTtffiUT fihm0lt q-{

.:mmn:-o, fulq I IClfu cit ~ C{){ ~ ~ I

~r;.n '-1 II'lfq

H2A~ HA- + H+ ".(11) ---:>'"

VI - K2 VI 2- + [H2PMo12 040] ~ [HPMo1 2 040) + H " .(9)

[H2PMo12V1040r + H2A ~ VI V 2· +.

[H2PMol1 Mo 040] + H2A " .(12)

[H2PMoI 2 VIOI\Or + HA- ~ VI V 2- 0

[H 2PMo l 1 Mo 040] + HA ... (13)

Vi - • +. fast [H2PMo12 040] + HA (or H2A) ~

[H 2PMol1VI MoV 040r + A + H+ (or 2H+)

... (14)

2 kobs == (k1[H+] + k2Ka) [H2A]o / ([H+] + Ka) .. . (15)

[H+] » Ka Jl(f: ([H+] + Ka) -[H+]

qct k1 2 = kobs / [H2AJ"

K H+·l 2kI2 =(k1+k2 a[ ]) ... (16)

~ f.tuTruT qc:: (12) q (13) If H2A <:IT HA' tnT H2A +0

m HA· if C% ~(;'Cf~I'i fuf.rm illU \3ilrfflICfl(OI iroT %,

20 '~ ~ I0f ~ '~<lR ~ qq 7 3fCf) (1) T 1999

~( ' C) k l , 102

25 1.5

30 2.6

35 6 .6

40 10.3

,\H " (k J mOrl) 101 ± 6,4t,

.\5 'I (J mOr l K·I) 60 ± 21.10

,\G " (k J mOr l ) 83 ± 509

~ I)

. :. I ~ .. -' .... A "

,,, .f:!,

:0 --J'-' - ---JII . . --~j-

;;fr Fct ~ 1K (14) q ~ ~ ~ it ~ iTill ~I

k2 x 11 1. 2

3 .15

3.56

4.23

4 .53

17.0 ± 1.38

-140.0 ± 4,45

58 .8 ± 1.07

0.93

1.04

1.15

1.24

---- --------.. -

k2 q~ ctr ~ COT qft-qyuJ (-140.0± 4.45Jmol- 1K- 1)

G:~mn %, fct ~ q~ ctr U-~ '31<f{m ~1.1 ~, ;;fr fct ~ .~ ~ AA ~ 0lICRfiCf)(OI it mR qr.n (-62 ,9 J

mol-1 K-1 q _ 69,5 J mol- 1 K- 1) ~ ~ ~7,28 1 k 1

q~ if !ml ~ 31cT(m it ~ ~r CfiT 'lR \ffi

q~ -?r J:fw-;f ~ coT ~ CMill % 1

3lT1ffi

M lClcb'l 01 ~ UJ1 l:f'l, ~, \i'flOl" ~ cz:rr:T

Fc:r~qfcn:--lT(1'?l , 1lT'tlT, coT ~ .~ ~ q (~'1I(ijCf)

~~~~~~I

tiG~ 1. ~ ~, :fr€! ~ 3ffi: .:iATcoT t::;'l' , #mrr11F. wr 3{ff

!&2(}q(rfi 3WT ~ ~ frrrq:,pmr (~~n ~,

~) 1 992 , ~, 99 .

AA ctr 311rHflCf)(I)I3lf~0TI it T«1 ~ ctr 2. (i) ~, ~ 3fr: ~ em, ¢ ~ f!i171TC/i ~ ,pfr, 35 (1977) 761 .

(ii ) ~~, :rrrw#rr~~,pR, 49-739405, 1974,

~o ~o ~ 37586 15, 1973.

~~ ~ tr ESR ~26 it Rhe; if ~ %- 1 kl q

k2 ~ 'lR CfIT TfURT k12 .3ffi [H+r 1 itJ tfur clW:' m1:fl 4,

itJ '3Rnsfg Q;Ci ~ it ctr TV-fT, ~ mrufr 7 if ~ UfffilOllil ~ itJ m~ ~ ~ rrm ~ 1 l'Il~lfilCf) murrtIT ~ ~ k12 Q;Ci [H+r1 itJ tfur m1:fl 4 if ~ mtfr 00 firwfr %, ;;fr ~ \3l~l ~ ~ ~:"@g e.-ffi ~, ~ ~ ~, (16) ctr ~ ~ CMill ~ 1

3. (i ) h.fr.f ~~n, ~o ~o rlR4,051 ,179,

(ii) ~, ~o rp.ro ~, 4 , 075 ,244 ;

1JITUfr 7 ~ qAT it ~ Sffif irill %, Fct ~ m\ 4.

31q~llOlCf) , HA- ~ ~ ~ ~ k2 COT tfl1" k1 it 10000 (25"C) TIT J1fucn ~, ~ Sffif iTm %, fct 5.

0lfucnt~T ~ ~, (13) qffi q~ -?r irill %- 1 H2A 6.

ctr~~lT HA- ctr 0lfcrcn ~~m, Tlf H2f,\+o/H2A

C~ fc:rqq = 1,19 V) ctr ¥AT if HAo/HA- &i ~m 7.

em .~ fcrqq (0 ,72 V) ~ CfiRUT ~, vfr ~ ~ 8.

Q;Ci ~25 itJ ?tefUTi itJ '~ % 1

(iii) BlW<:i'T, ~o rp.ro rlR 4,301 ,031 ;

(iv) ~ ~~, ;;rrw# rf*c ~,pR, 6 1-23020,1986,

(v) ~frfq If-f, 't~fm t::;'l' -.3m mST t::;'l', ,pr,'?Jiqri 33 (1988)

555 .

t::pn~fm ~, ~ ~ -.3ffi: 10000H'lI(1~~ , rifr;frw.r Wr r;sciRrs JcHJi1f;;fhl, 2 (1 990) 1 27.

1WR ci'! n-q;, ~ if<Tr;r ~ 144 (1934) 75 .

<li"f01 ~ 3W ~ ~ q:, ~ 3fT1fftq;- M'mtt 12 (1973)

1404.

!fr;nils }ITT, ,:mc vrlfT Jf1ff(-cR WcMf ~ 82

(1960) 3464 .

~ ~ ~, ~ t:(lf m -.3iR ~pT\R t::;'l' ~ , VFIr7-Jifr5 ~~73 (1969) 1996.

9. yiitJiil~, ~ ~ 3W ~ {, r-r~~ 15 (1976) 2898.

1 O. ~ 3W D:, ;:pf,;r 3Ifrli ~ fiiifrxti. 72 (1968) 891 .

11 . %fcrI;h 3W ~, ~ 3fT , JT#r 3Ifrli ~ fiiifrxti. (1970).3388.

12. ~ m. t:!.'fi. 3W ~ ~ cfr , JT#r:3fl71i ~ ~(1969) , 2930.

13. %fcm 7fT ~, JIT!R ~;;R(qc:rqti , ~~ ttm) 1962.

14. ~1I~il~. czitr ((TT5 ~ ~ 6 (1963) 66

15. ~ D:'f iT 3frr ;;pri ;h 1Jl1 , r-r Jif1f.rq,-~ 5 (1966)

1249.

16. ~~, ~#.rs J#rd?r(~?ro) 1970 .

17. ;ffiir:n ~ fiicn c;'l. 3W 'fTP-ll em. ~3 (1984) 607.

18.(i) rTrWnUW-r ~, .3lffi 1Jl1 3W ~ ~, JT#r 3Ifrli ~ #.rrrb f1ffn jfrw;;R, 2 (1991) 781 .

(ii) ~ V'l, l:rq)l~T n: 3W ~ UJf v:I , ~ vrfr7 :3Ifrli iliift¢. 33 A (1994) 219.

(iii ) JIlfJfC: ~, ~ if 7fT .3fn: ~ fT , ~ JT#r 3Ifrli ~ 55 (1977) 3581 .

19. ~ ~ 3W Jff;rR &r-ni. ([CRT Wirw 405~B40 (1986) 79 .

20. ~ t:.Jq, Rmtn t:.Jq 3W ~ ~ . ~ frcr. 645

(1978) 11 83.

21. ~ c;'l iT 3W ~ iT t:!.'fi. r-r Jififf.rq] fiiifrxti. 14

(1975) 953.

22. jil.;il t:fT 3W ~ 3m, :fr. JITr. ~ ~ ~ f[?7. ,

265 (1967) 723. ~ ' ' +' ~ " +. r rTiF..-A~

23. ,<~~'" ~. ~3lT 'fl0ffi ~ 'fl , Jf7r7 ifl/i'7C/?jf'l(

J;JfPtfrm. 18 (1983) 299.

24. ~ ~3fn: ~ c;'l it, vrfr7 3Ifrli ~ tiiifP.tt. 79

(1975) 92 .

25 . ~ iT t:.Jq .3fn: ~ q;l', r-r JIT1ff?q) Wfrw ([CRT. . 74

(1983) 221.

26 .{i) (WIl"1lctl m{. lfR'iR t:.Jq t:pJ3W fqfr ~ c;q, JT#r:3lfrli wilH);;fM('I ~235 (1960) 260.

(ii) fqfr ~ t:.Jq. <1l'il"1lctlm{, tmlR c;q ~, !1ft ~ r-r q/qjr;fj;f}qj('l ~

(iii) ~ c;'l. CJ:B., ~ 5C<t ~ 3m. c;'l., ~ 0ffi.

3lT . . 3fn: ~~!!l (~?ro, ~) 1961.

165.

(iii) <11'l1"1lcti m{3fn: !WT ~ c;q, ~ qJq}f);(.¥m

([CRT. 50 ( 1962) 62 .

(iv) ~ m (iffIlT , ([CRT frj;-rfjw ?iiAf¥h7. 18 (1984) 562.

(v) ctrfRT em 3W qqr;j iT, ~ 0/lfl?<;,iii'IJ('I gritfZ7. 19.

(1971) 718 .

27. CAm cfr, r-r Jififf.rq] frj;-rfjw ([CRT. 53 (1981) L 1 3.

28 . ~~D:. ~~t:fT0W~mnt:fT, JT#r 3Ifrli ~ ~ sfr;c;:r ~ (1993) . 3489.