The thermodynamic dissociation constants of oxalic acid in water

·~

· SCIENCEI

LIBRARr.

THESfS

copjl.

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ot the

•tlU~~ 'flrJ~~!ill~e~~t' the

· £J~t ~eUi

31~-B~ b3 ~~ Pb:;r~d;"'~t-let!tl.

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vltidl ·the

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l'Q~~a~in el~~ae. ant~ Ash~· a.fd t~lth the

for m~4"1®1'd e~ts that

fol!'

C{)tlS-t)qt:ten tly

to t')Ul:f 2 .... 1&~:.

~ollo'itdng tabla gives a eGl~par!son of t.b:.,

·fK.,

n$tllMs ...

#

Jen.~ .flM V~el• fl~~ md Vo~l.. and a~

~··. !-.c, ,.

rmd

Inti&•• ·

?!w valn~ t:tt Je~ ·~ V•l·~f!~ tt1~ r~t.

·_, '

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£tltttar1e

tl·Jiml

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lt .% 10;

1· .

179·7

"-6~6

1~) ...

6 .• ,.,

lt-.1Ji

a) 2b

-··

.

'4'

2,.0,

2.!}4 _'·%.1

,.,,

3·71

1}•53

,..so

~nd 1~1-ydl.'"O!ef! 1m1 ~:1eti v.t ty cllaffici>::m ts arising :f*rom neglaa-t

of' COJ.'T'e~t.:Lon~J ~ :tr,-,m application ot• partial e~.t~:me for

t;1·le potentf.rll ot"' tha .liqttid ju.ooti11n batt~e•n aatttr'stad KOl

(4,.1 !1:01 l4J~~ ~lec-tr()<i~) and f!ooium tual1)natlll buf:ter

eo.luti <>n%il ~· ~~J:ltl sho-wed that partial cOJ.'"Jtt:l'!ttiGna p~uoe a

lt'<Jrgar e~~t:tJ:• 11:1 th~elll qu.ar~ ti tias t!mn no eGm:ectiona at all • .i~n ~rror t'Ml snlt~ 11 a.s .. ~ in p,.:r tiUil:i/ prodttC<t :tl ~ltange as lo~

as 2:;,~". !n uina'~c!ation oo:natan~ •

. In 19;P 'ri:~'tl.*ned and om:m12 t~ih<>wfid tbat it was

VOS$1ble t:J {iei:>~rmintl the dioo{)e1st:ton· cor~atf.i!tta O'f week acids

fhUt

tgpe.

C1U~JU. ~~·.·Ul· ·1,9;2 ~atfl•t~

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tlta tw~GS'l :ton

:ann

tb.e•

(1 '··'

...•...

.•...

...

.

ret~ in

the celt''

m.olal CQnoentrati~ns

:tooic: ~n'}Qeica dauotcatt

themooy~ie d1aaoo·1atioll <!'om tent ..

X..

of

eaet1o aeid ~~ by t"!e equst.1oo

f!f t'Ac

:p~ .. · .• ~·· ""'"'

1::!11 .,. .. :.H(t ••••.•••••••••••••••••••. ., •• (2) .

e:liruinsttn~_ran from equatiG.ns (1) and. (2) ·~

-a:r

artd

bW

d1v1tina throngh blf 2•·!}oot)

T

"""'"'"1!':'ll'I!F. log r.tc1 - log ·

~c ~

1-osa.r:i. tm auell a gttonti ty as

Harn~ :~::ibinso~0 _{and by 'I'T<'3'tf0t'!l"rttlr.'!:}

t}W i~nic

neerltl 0 t>btnined.

'by

ratio ht:~s been ahcmn

<ft)

•,)wi'illl" ~ 00 VG'q

there-:f'ox-a

lf

jJ

~

VGl.,"'1/

lii:ia~tat~a

a<t•tie

a"Oi~ and acetatt.J iQfi :!on the a'!Jlution~ !he

. . .

· ~ mul&J..:tt¥ of' the llndis-aof.d .• tetl nc.fttio aeitt~!'c will b&

•t,

tile atoi(l"liOmatrical •J.al:f.ii:!l, leoe 'tl'w mQ:J.sUty of: ·tluJ.

itle.btste~l

soid vmim .

ecr~

1 to nt

11.

as

stmtlmtl)* t..rm trtte raolAl:t.'Qf; .{)eft· the

.~'$til'te

ton

·~•

11!.11

'bft

e~~tal

'ttl the

t;talehi~'b:te&l Jiro~ittw

oi" -

s,(Jdfum

. ., ..

e~t$1:$, \ihie!t is aatlnmed.

to

be ~l.et~l»' dtaaGCiat-ed •

. ~· ·tt"'l&· mOlalttv o:t th.~ a•tate io11. f'1lltlflt~4 b8 • • disaotJiat-. tt:Jn ~ tl!~

·.

aeet1tt ae:ld , 01:#'

:rffi;~,~·

'Thus the G$oo-nd tarm on · tha lett heco-~

log'.

(m1 - mn)

~-..

,iii'+-~!1

In thi·:1 _{tel!'m- m1} lil:2 snd l'l.t; are I~l01f.1.n, assuminG OO:r.lPla te

dtsa:Geiation of the enlta, a.nd ·~ <4- must be evaluated

~1llU"~ximat1t>nn. i!J:,, clatermiue a prelimlttal"Y Vflltte of th.e

dissi}(rist:lon

acn~stantt ~;

tha

stoiehe\H:lOt~icnl

mulalities

of .a.eetic aeid, aoditw aee tate and. aod.f:rmt til.l~.nri de • _{m1 ,. m2}

and~·~ respectivi~lw are s'!ll:Jatttutad in _..,. t!v.t second tam on

t'Wll left of equatitm (4). f~>,r tlt$ t:.t'ne. t!lttlsliti~s mi.tAc 'mAo

~d

fileJ.•

The cm"ve obt!\in~d

br

plotting the lef't e1de

tlgsinst tha ionic strength, _/1 .rJ.J tt ia tUtt~apo~ti'ld _: to OOJ:G

/u

/1-'

_ .. ,.. . ,_ l 1 . 1 1 .

s;;> det~min-~.ug - og li~.

or

1(!'₁ hom wh~"'l

x.

₁ 1a

4riarmi?e4. Tha preliminary value of t:₁

~

1.-e.

xi,

ao

obtaif~ad is substituted in t-'lul .eqttstion f:or the thermodynamic

mmJI·

me ...

lil~eh ~ ~· '~tton

· +

la!£t) ·

m

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t'bs.

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arul Em'b5e1

4-

~f!· tt,.it:t'V~t:;

~ ' ·~

ooeff~~t · hl

thtn

e~mtifln :ia ~pla®tl

oo

an

·~ivP~ximattc,~ 113

the values

of ~

~~lu ti~tla:

d.etarmlnl!lfl b1 ·

'!ia3metl'~;

..

• ·tn attd!um c!llo:c'1d~

v...- l~ c.t.. ...C ~ .Y.~ -:o.l.f

this $~ttatit)n, mt{1t tu~e t'nti.tt1 k.~own

t~;}t tJG oolved fai.• mli• 'l'hoe velua . ()f EJtt so

~na

another

oJttrapulati.on ~"rteii ~t to cletermtn~ a

s:eoooo

mltm o'l Ict1 1 r-"111• This methoo Gf' aoooesrd.l!':e

~vPr<lxl:matioos

t1l oontitnta·4

x

_{1 and.}

mn

valttes are ol.'fta1tXt4 f\ilf'1ll.

tlte ~~mQ1lts at· bOth ~qnatton11 {5) and (6) ,1> va1'Wl

oe

~. 8a obtainQd bo:ing . ~aeGt"dad aa tl:w t~o~ami.c

In ·,.,.,,.IU.ma

1'

t~ae~ tll~

cen

· •

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ift

~

{!llf

h

l<na

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(lli.J!)i

~1

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MJQ:Ic AS• .

to nle&Qtlr~ the: ueond dJ.oooc!at.if1n ~natt.mt p'b~p,ll~i•

tttf!d. et:t&~Qe:

ot

til$:

•thoet

empl~· ~a th.st,th~· _{::~ .,} .... ·

- - .. ~

at$seJ.tristt1cm eat!$taflt

' -~\ \-. :, . ' ; : -~-·- i

ta

' obta~ .

from

sl'e~t~~tt~. to~~ -- - • ':,:. . - l'_ ---1 • . ' _--~·-_:, _ _ ,_~;-~ ' . ' . - .- _· · __ - - - _ ' .• _ · . :.~-- ~-':.·-~-- · - ' · . ·

mila4nr,mentA uptin eelle

vd.t'htlllt Uqu14 3tm<t'tio:t~., •ut&~tng

. • ' k.:·:.:,· '

cextrs tlltl~4~cal •tito&!

of tlte n&by~~~'ttt~ka 1 11rd tins

ftme't!Ocn f:'>l'.t: tlte tilotivit~r eoef'f1.eients Of tl'la ions

;tnvo :tv~a.

th~. &qttt~·t!<m

m

1i! ~ - F lrt · :tH :f'Ol l1Jal • •"••• •••.•••• • • ••

•*

(7)

'1~~ e~tion for tb«il aecond dinsf)c.i~tion ®ttst.~J'lt .of

ph;::,e ph.o:trie tlelid in

t'tf f'!ttil{)Jt.

fff2

·~4• I

ltYi

•11!.,

~:>4.

By ~ill$;t~ ~ · .~ ~quat:t~a {7) &rld (ll) egmtion (9)

ll

obmined

'f·.&pPllfin!f the

DGb~tiU(:kfll

f'O.rnl:Ula

$~S~il

whewa '••

Z..,.. ere .'the• 'fal~

ot

the 1~

_,

A -

8

_ . OO!letants

to ..

th. aOlVOdt and SOlwnt atui

®lute

.-espeottvely,.

which apl)~lmation

ts

ac~te

enough

tor

the

weaent ...

k,. t.be

laat

teem

ot

tb•

equation.

(9) Sa

seen

to

be

s.J:vtm.

v

"

tal

taePOt.

los.

·.· . . . · .·.

tl£P04'

· &¥ subst.i

tutms

thifl J'esul. t

1n

equ.at1on ( 9) the" le

tinftllV obtained.

+

2A/fl •

(10)

E represents th& •asu.red electromotive tore(:) o't tb.e cell.

E₀ the nomal electrode potential of the cell

ll2 HOl Ag01 Ag. ,

m thi; molal oonoentrat1ona of the res-pective subscript

ions, A the theoretical constant of the Debye-l!uclrel

tu,tuatlon,

y

the ionic strength of the GOlutiOil-1 K2 the

eecon<t d1eeooie.tion

constant or

phospho .. 1c act«, and

a,

a

-c;;rr:..-~- (._...£2..

OOJJ1Plioate4 tunct1on of the oonoentration which• wb.Ue

e£;leentially constant over the concentl"ation range em.plo7ed,

need not be ~value:t-d. It 1a tmpo:rtent to note

the.t

arrg

alight

error.

involved 1n usine;

equation (

1 o) becomee

progxaeaa-tvelJ'

less as the

concentration ®creases and

that

m:a;,gPo

₄

and.

n;

₁ro

&lta t~ ~o~tt._ -~

t..'1e

salta.

~~.a

~·

al$tiOOiaiad•, anti

d~

dh·-t(t.

c&--t

~~~

. i

18:

••11

-~a·

lllth.

ae

~;.~~

. . .

et!ipl•e4.:

ari.tm.~~

i'ilrdtt

#lsht - -

eta•

&quatton.''<to)

~

....

-r

b& ~ted., k plottetli,~t

1~e D:1:f'Anlrf'&tl ~m1· . tbie tnt~~~~pt

gtws

te

'Valta

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eell thit aalt ~f~ct Off the (lttjlnJ.1Yi~t"O'r1!G

SCOtl.t"tli.ltg t:> ~ffr!gb:t

17

to tn.t'lrll te tliltttion, ~

jJ.

~~

~is cell · aift'\l~ fr~ tlt.e """ ... usU=d bg

~hle~1' f:t:'h: acett~ ®id11 ml;J t..~t

a

i.a ua&t1 in plaea of a

Olt.~l!e aeid ·- pota$s1Uili Y13'4.rogoo Ol~alat!!!

in.st~Gd of an ~tic acid - ~~lditun a~etat~

·~· q•···.~ tbil til•ooiatl® .of ~Uc

af:id•

f*~ ·ot t!da ~u

-te

t.> •-·

S:iat

«-~u~- -~.

"t~c

•

~u..

..•

#i& .•

io~•

··

•lE~$UJ~ ~1ootromot i~ f'~~i:lt'j

~t!'t:~tfa potmtlttl ~1: tho ._.il ...

et~l:ic sc!d,

DO'I~&iBSl.tli'!li m1lo:rids ,

ltw;:trr>gen itm

llltl .

must· evalt~ted by: ar!thm:~t:1cal

and t~ tr~ aiest)ttiutiOB ~mtt K

•I'J!i:>~r,;.jf;l!.fil bJ

a

iS'Gr~ ·o~ ~~eaa!~ ap~~-tmattone.

constant o:t ~~lte acid anel\lf:.l}U.S with tlltit

N~i6

.

h~

t'b.a die.et)Ci$t10'ft of

ph.os~"torie

. .

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...

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'(ll:- J'

""'it .. _ ..• ..., ·_.-·· •.. ,__ it~ .. . ...

. ~~·. ~-·_·· ~

..

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a·

.the ·~ tl'letrt~mt1v.e t-o~ 0~ - e;a;ll;

Ml~l:t._.l..k-.:>dtt pQt~nt-ial

o,-t

t'be. -c$11

1··

q;.~tn~~~t6re.

ml

I

AgOl \

Ag.-th$ t~t®r&tleal·

Dei~ll!lf-'r-r'ooii~Z equat!w.- · t..'te i0l.11(1' ·~~t tbe

&::Jlution~:c uQd

.n

a oomvli~t~ !~ct1oo of o-c::meen~ttoo.

. · ..

11~· n~l ~1-Wodiit

pot$nth:ta

cl> -

4D~o.

$ .

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q~W-fl

\"1•vGtJe hfi•Sit bee

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!;)f" -

el.ee~oU~

ttl~ o:t thtl ~n

and

1Iihl~

1 '.

~~is

Pl:O(:t:Klttt-e gave the nol"1n5l eleetro\l$

pot~ntial at' cell (1) and ne\"1 values for th1l <Jell.

l"t

~ot

1101 \ Hg (t atm.)

f.fhe V(lluEta obtained at 2;0 .,

,oe,,

and ,;;~o. w•e

'!'amp.

oc.

Cell

(1) Call {2) O~ll. (3)

2;0

·--~-774 .222''

... 6!'96'

-.6,,

,00

_{... J;-.7707}

_·2t984

_-·'9600

_-.6$b-,

0 _-·~768~

·215~

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a 11 ttlce

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c()~iat.a

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a!l~~t•l-1 .:{5 a •. eq~t:t f>f P~tt:i•a

plattmw w~ it'ikh in ~ -~~• o;jnQ:lctc

Tl1m1

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. ',-:',,·

etx milliamps p&r el$CU'GdC> for lm l f $tl

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m

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wi

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A.a.,

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on

titOOlN's:h ~it.~ a lltenil~ potas&tnt.1 P~i1~i"l\'te!ltJltl8Wt

aolu:tion t'O " 1:00

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S~a;t~&· ~_a aolutions \'Jere •a's _{• :.l.~-o.·;-:-} u;p rd.tlt _• dtatillai t1fitu • ₎

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tll1asoo:tat10'll oo11atsnt \IQS. mad& u.p oo foll®,$J- A aol.uti()Jl

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ehlJrtde tl) a standardis~d ao:l.ttt.ir1D o~ ()xalitt ncid. ~

Vte1ttrdk at" vo~situn h)'dtogen Olmlatt~t tle~n~a by a:ntd.us1e

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_,,

:r~ed atJii·wdE~tt'

1

8 lil~k

tbu:t.

"'.. . . - ~-:~ ,- . ·. - '

b$~t~e

•t

ai.f'ftlaton or

quinby~®~ t\) ~'1.•

stl,;ez ,..,..

~~i1ve~r

~ltlo-r1dll) eleetrt><le no eqntltbrinm o.o.uld be fibU1~ ~.Jclthoot ·

. .

t'tOmPlet,a 8ePQl"atton o:t th~ ~· ele:c:~d& oonrpal;;'tments am!

z.

A :; tti~li. atope:oek, fJ• anil

1 -

B ems., of ;l

captl.~ trtl~!ng e~ "th&J:.•af~ tnto:&"t1uaed betw$tm

In u~tmGnt l~ a silver - a11wr (!hlo~de

eleett"'de ~1tt:at1h$d t<J a rul~~ s ttlppe:t" ~ was inatlrted and

:lllterctu.7'• t?!~~irl. qu.inhytl~ne mora than atL..~1oiellt to atll.t~'ltG

, '·:.~~;:Wl:·· ·.

c~l.i be· ~1t~&a wtthont ehanglmtt tb:& 1$ar!$.~ •.... fl1~~

·whiCh~ '&1,/b~l$nt~ tl~

aome

of'·.~.

Ctall

s~~t$-

.•

hlltl

sttaf.mii.;~~ &~ wp~ P~a~

· the

8Glni~~ni'

waa·

bu.bblea ~~~li 'the s.t!fb,rtf..~n ln the lle~l. ~·· a!lif····~·

. . .. ·~.

pae:rJEhl ~~l t1~

oalt.;

fJhi~ WQ!S· ct~nttn~ f!Ot! ~ ~1'i1llrt- ··

tb.en,.

t1ltt

ni.trQ;~ tlG'fi!

ln

thi;i rtc~l

nnf:llt

~~& ~""~•

and ·ibo at">ltttion

~&)~~d ow~ :ta:~·tQ t..~ cell~···~\··;-··

tO' l!'ti~ etop~. ·{St., S")• As ~· ool\tt$~n

i1.Uwed

,,.-,.c-'"·;c~:

i~to oo~~trr~t D ·! t $t1~ ttp ttt~ soJ;ta ~~\t~r~~. ·Cin

contplet1o.n the filli~ a.paratio~1, t1la sto.r1o.Q;(tim .&ni!!

the~etat.· ~·~h.o- stoptJO.(tk c was l'!:ept c:ll)&ed 6;-{cerJt ~t the

m.{lment o!.~ ii;~rul.dirlg the aleetromotiya ·f~'S·.,

~w

aooona

disaQQ1atil'lD eooat~nt ~ mnmm~d &t

25°

~ ~~

..

S~ttd ;;;0

c ·-

tlta firat diaeooiatl~Jl eunatant at

25°0. onl~. All OtJlls atttd.n$tl 0quilibrium ~lt'!ct:tn

,o

to

4-5

miuu.t~a on::l re~i.ned c~natent fbr at l(fa&'t ; houra at

2:5°0.

art..d l$aat .IJ. bt.>tJ.ra at

';On.

In

1eol$;tw

~s

•en

equiltb%1wa v~ not rftaA)'hf.ld -wtthtn

4;

~a

wu.re

dit)eard~.

~lla war~ meas~ tog~t~ ·in dt\Pl1mlte ~

tr.:tpU~~ ttnd tho NWlts given~~ tlle ~·"With dtnrlati"ns

.i{J;' 'f. . .t..'t~ . + II •

·~1 ~~~--·.·

. .

~·-:.~~

tha! 8114

.~1--

Wdtli.

•

--~pt

....

ct

,t::"' >

t -... ~,n~

'tibfft•

1

. . .

s.n·

tcg&

tbat • •

~te· ~e ~~· ah"Htlu mt~·'\W,tth tlel.l ·

&&~t!r~•• ·~l$

•1.1·_.

•nt.

to bM4le.w"•

~

Ut

~~~B~tth

4upU.-.

·~·

me

tbet

~···or

•u

a$

25°

ail: • oo aitreMntl$ ·fte

o~.t>Ve'tiJ~ ~

ttm.

~tttrea

to~

d.m;e

J.;~~,ange

used.·

$Qid.l1hria,. the eqtUUbrfum ~·~· G~ ·tlltt ~gth

··cfSlle ~ined at ~libriunt. A.t ,o:~

..

•11

'War• Mda ldth cel.J.a of tha ~lif'ied

.'tifP..:

.;\

ea.~!~ Ina~nt

oo.

pottmtt~t• with

a

6- 1.-8

voits,. atl4 an.

QqO~SO' Of .•

o,

m.v ..

vu.

Vf$Qton N~l ca11 use« • • ~e by the.

•b1 _. .. I

~~ita

.. .,_.

va1u~a

ttf

tb~ e.l~itV#

' -· - - ··_ ' . - - '·,.· ' -. . '}~-- -. - '··: .

:r.-

fit··t;0

c.

01:·

thac~l1

tl$• to

tie~

tb.

a~

;.··aiasodG:tion·

~nst.ant ttf' o~ie ~- ln. the f~'t <t3lttnm

•l!•

~~d~ttt

t'bie mola._M$s

:'~

.or.

the

ea1ta

~s ··U~J· ttuJ

cell

. - .: '·' ~ ._, '-' ·•

-.·so~J:lott•

·

\ftte.··aQeon£1 ool~ ~~

tho

®~~l.titt

' >\~~lJ}J:_.. . . ' -ii'\; ' . '.~ :' .· .:

Obse~d' · ·of t1te e1~ctr0~ttv~ ~c0,e tn

v()lta.,

the

ttlf.r! fH.tltunn, t11!i! calctll.at~tl !etttie: at~'G'ngtlt~ ~ ~.1 th$

last litRJ of a~~ll 'l~l:Jle I, !:.£, !!I j' ehG'i<m

the ~~t.~btad value of'- log ¥'~2 or pX t'b.;a ~t:ao value ~

th~ ~O:nd .fi.iinaeooiation constant

at

z$1--u ionJ .. e stD~lStll.

~bl~ .. 151 ~eoortls tb~· vnltWB of" tb0 a:t®trotiltJti"Ve

f~CG· Gt 2;:0 Of tlle call used: ta. dete~tne til~ ~at

.;,;-<ltseoeif!tt~:ln {!Q~tant ·.()f oml1e oo:ta. rn th.~l. first qol~

~'''•~··~···

·• ..

~-·r•;

••~a

• • •

~l:: the

rlfth ...

~

·

-~-14~i~.:'.~-·-~

t.· ••

~··~.;.

•.

mr.r,~~

Ia '

~-~--~-...

o;,·~;

:-.o;i~6·

~·~o~''

\~Cittos

.

·:,.ot28, ..

:··-~-··oo"*-i5

',.{K1;f2o8

·· .o;1'i

. , -.0:5421

.• 02l~·

...• 01710

. • 0128,:;

. • OOS54lt·

., 'I"'.A~t...-­

··~~,

" •OO!U'107

~~-·'"

vnl:te. . .

-~~''''

·.u

. ·

..•

~~·t4JJ.5 ·tt

'1(~ '*'~~~ Jt.

. '.,,~,

. . . . -.;.,~12;J6 !!

- .. 1115 ti

. *.-10;2

··-.0024

·- •·1 ;81} wl tfl•

·.· "14h$ ·' :~w1lf59 tt

. "••1'7:5

ff

-~-•.• 121.f9 ~t .

. ·-·11

61 .

.ff

.· .. ·-<.1o;;

, •

.

~·•0949 n

·-~~.01~1 n

--25''

. "•ti11

. :··'128;

-;~s;;·

··ob2tl

··~

..• 0,21

··0160

. ·2?'5

. .

' .1710 .

.1~8}

. ..os;s

..• o6Jt.1 .

. · . ..

0~1

..• o;21

. -.0160

0 _.~;aG!l -~Mi0!7

-~-~~

.4-,,S&b

ll--•5703

.b,..,5bo

,.q...;~,

·.D;1J2

.o~--1~1t7tf.J.

'*01,1b:l; -.-008'5lJi{• ··oob~1S .· .()0)208 . '

--.1;18 ·

YQl--,

- · _•"'-J7' ..• r.tfi~ ' _. ·f.l

·-·1~ 'tt·

... :t1:1'5 ..

~­

·-•:to81t.

.·¥f.

-·*"

tt

-.('iit{ft, . . ~

'-.o6!;4.' \t '

r 7 . . _ • • - ' t t 1 i H 1 J .Lits;P'Ji • • * 1,·, ·-. ...

.=·

.iWt

~ ~

-=

~

I I' T . *';ot&:!l I ,,,.._atl'I.U

·-0~959 .o,;~ •P2l';'Al '.,t)1,8~

'-~'''·

. ·OOOt'!l

-·~'''

.·

.ooa~~7SJ

i A9um~ t\l

'be-. •li"o · tn

t.~ :fir.s.t

a~:d:mat-.

ton

.... ~l~Jr

vo:t

Ual

... !78\

@

··f'J;r' F"t.

. '

"""-~~"t'

-~ .. ~:!)1!)

-·2500

.. ' ... 221'4.

-·19,,

~.t64.3 '!'f.

,..;;,a

·li.~· ~~tJ*l'

-~-t-1"

.

·0992'·

•c06-G1

.• 0~!)6

.o::;96

•

.. o,,o

.•. 0198 •. QO!l9

'.0049

0

4•"''

4.

s

ZJIJ'ii ..

.!t,

Ft~~ At'J>•;!)~~tf.en • aeaum~

; -- ;c _-- _, · -.H _w(

··04Sl~.

.o;~

··02lt2.0

::', ~Ot)S1f .

;o1t:i;; ·

.• 00)1,19

~Oil.,!)~ :..0(1it.!,.J". .,OJt.:J!)!/ .o!§;Q6 •02480 .01$J~

.. o;

.~!)1;9

.001~'''

_OOf";Jt;..,O

... ..;;;.'i~l J

•00951

·~ooa~

.

~~00725

. .ooli5;.

.-.oa6i;O

·00465

. ...

..

oo~

.Ot'J18o

-~2941~ volt&.,·· ·

.. .,a{&,. tt

.... ,.2()6~ .. ff .

-.t;rs · • ··

•.2;c,.o

"'

... 22{lf,

-·1963

. '

..

~·16%-;l

.01007 . 1'•2941}. volta.

. .-00869 -·27~ u .

007'1'!\ •.··1""

..• ooo,,

.oo6,5

.0041}1 ~_()0,0'8

.00184---~'4

-·2575

-~2500

- .. 2274

. -·1:9b;

~·•i6q.;;

•1037

··014!J.

-.oii69·,.

.· ::;;'i'.

.• 0!4lf,.S •. o1·2;t

•OtJG7

.toga

~07ir.8

•0513.H'''

.o"G

·.: .• 0,4

.02~··

.01'0

,.oo6s

. "'*'222

1·''''

1,.6,79

1·•7140

1·•728;

.... 1a,;

. 1··8174 1.8887 1·h120

1··'515

1 .• 63~

1.699!

•. 1.7'i;i0

1.769()

1.8182

1.8625

---~----~~---~~---~~----~ula·u~.a iD

a~~~ltlttMi,~onsts•.

t•

(11. So)

•

~ ~

i;lo-s"att""

,..,.~ . . . 44 . . . :La m£lasu:red.

the·

mC'ilal.ttlE.la

. .

•lt1t'f.laU~n

·at'

+ali

ljl'.

f'~ee

O'Ol1tatns

i=-be

Gt'th$

'U-"'1.1~·o.t.\';~;~ 1n tlle

tho moln molalitu

p:oteu1td.um o~late and &fllt:ml.

~tas.sitlm ehlilritt~ to within

¥1h~e ...

ma·

= ., .;:;.::.

~'

'l!'i!l mr~ .n

=

m.r._n ~ m.-.'1

~;t;""'2""!r ""lit.~-~ ~·

!Mit:: a'l"c'l!'Of~.llc1gt11.-.

'lW

Jl

=

ionic strength

m ~ the rDOl.al1 ty of eac~1 inn

thin lute

{r.t<t) pot~et:~1ttm. ~late ( ft'i.2) , at'ld pataaa 1t.mt 'C!llt>ri~ .fm;s) 9

.•: ~·

:ten

eollG'\W :

+

~

x

<lat

> "'

lCz"~r < ~· )

(~;)

K2J~l:J~)

<m,>

- r

x•

(~)

•

r

_(1rt2) + Ci'_{4 (m2}}

...; x•

(my + oi"'(m

: . ._ ;a:

t;Jt;O.>t

!A

.flab

c:i.) \.# .. = ,.,.

,aoo.

u _1:\ti

.;-to

,;o(:!.

H

=

.;17

tat

=

~

=

m'

= •.

051325

:So

=

-·4774

volts.

-. -.16;:s·vol.ts

,

=

.o;91-~ (tllUk• i'*Det'1'hof rr~d~ Ions

1

::~p

\,

Qn. t!l~b$tltttt~g tb.•e~

•J.nu

in & e~tl~

1bl

• ~1).$

!a..;.:

v . .

+ log. _{+ ~1}

.-,b.--, ..

p.·

the ~qn~Ullln ~mae&

-·"'

-

lo~·~!f

+,

y~

~ d;.·

s

o"A'J-.

t Jag., .o;-1~5 + t .012

."

,

.•

wh.1-eh value ia ta~wtt in tt1a tour-t~l. eo.l.!mltt · -~~ !bbla . I . · 'i·wafled - l-og 11.₂1•

~4e

ionic atrsn gtb

•2566

ia ta-bu.1ateta

in tT!S: t~lb.'*-tl'•!tGlUl'lm,'l51t:tilar-1y _~

-

a aeri-f}a ?.if vs.ltt~$ _. ·f-flr' - log

R~,i ~

w(}l.'i[Qd out f'JtOm

c~11 m~uJl.tre~ts

and plotted

. .

a~b~£::rt ·th.a ionic et.J.""'engt:1:t1~. ~I~ha pl'lt S':t o.h~i.ri~d :is f'mmtl

iot1ic otl'>Cf!L':th &'fterl~ t·'h.e intere::e_r)t is - .log !:2. or plf't'

':.P1t-e tlloto l:or

25°.,

,a

0 11 atac1 ' ;0

c ..

a11d 11~ extru~lO-lationa ru..~

ahQWD bN graph I . ~r'h,e values {}f pli:.,_snd K,_sil abtainad aret

~mp.

oOo.

pX, It '2...

25

1H~,ao ;.012: X 10-;

,a

_4·320

4~787 n ~~

,;

4·~a l}.4!;8 tl ~

, /

Tiw f.omula tt&~ed in ealeul.at1~T the tf.Ht

.··

--~··

~~

fh~ r·~t t . . 011 left OT)D~ln$ :So •l'tidi H ~-- alii

~ra.~•~"-

t8

~&~~.

Xn

~-

te:arl!.,

~ •leUtfs

: ' . ' ' ."·_:-:;

a~:

tl~f1ttaGcdnt!$d··.O"ml!e ~et'Ll

srd. t.lU#

-~~~---~

·

·

•·~ae

₄

:"~•:tr;ln-.1. ~J.tld~.,,

-•

-ep~xi•tt:~rl. ttas· ~ tad a t -~

'to~-"···._,..,._-~----

1' .

~----_

.. _....

'

*.,.. ·~ ~~ 'f't'::-:'~ ... 4

.i:.;iilUAu.,.,.. :&oc<> m;l00 -Of/! fl'Oiatw ~{t,f..<4. ~ ~~-ll~

:i.n

tn Ca!Se -{)'t" f&aie •c1d·. and

l~\~~ght

1

1'

M'®!ll1U~illr~t~ and eince

e -~~~~ger aei4 than

n.l'lt\'~l to ~rs

le-ft Bide o'f· the

ionic 3 t~t;~ and if'

~n_gth t.lte

l1

ti ~s ~"1 ~ of'

o•U"' acid,

"sPeQtive-..

H

(a'

=

~i '8$ mll, is ~garded ae full; 41sa~f.-~d) 1tsdtom

·by pi,$t <

t

!» ~J)h .'! ~a

nat·

puri ·. ot tl'ik·' ~ i

'->·

eo~.:ees~ndli».g to.~~ t:rtl."'tmgt:i~ ~l-tt;tioos)la ~~p).lG,.ted &l!l ·

el~n, mil· th>$ val.t~ of • JD:g X~

.0

de~~$1'}~ ~~

w

~lculato

xi

•ie.~

is

~t:t.hBtiltt~

tn tn.e

~~uat¢{)n -~ ·~·.

- . ·---.: - • . . .: . . - - - -. -- . . '.~~·;'>~[.·

theu'mOI.iJna first di.ss!Je~trit!{)!l ®ns~ cf (llmlf.:tFaa1d

. : . '• I'Wl,u

{iii~ + mt;r • ...,_ "·

:tt, • •

·

'tnt1~ ::..>;~~,~~?

fri

m1:.

1_{l~'1>S r&qtli~~~l valwa f'~ t"-;t tel a:ca obta~1!l f3rom t.'l:la pap~}

i"!t!t

of TW~1r11ed and r-ram$r~ "•

1

In thin lil~ti

a

a~ml valt.te t.)f tt₁ 1~ detf.;}rtrl.nad w"hie\11 h1

tum ia tlSax~l to ~lnu.l2ta n-&\"J valu~ of ~· sue~aai~

·'·'~-approld~lti01lS of' t'h.is type: are twed till 'ttalu;:~s o:r lt~ and m... •. a~ f."'\)llnd '\VJ'hie:h. atitbfy l»th, Qqust.ions.

1.l . .

Plot II~ Graph II* tr'Jl{)WS t~ eithth and fhl&l

p:lo~. ~re final valtl~s lJf p:t,• .. log 1''1 "tie~· ~d to be

0

=

i•?GJ

,.. .otti8

fl:PP~~t~~n

t'bft •

·~

.. alta

~A

.. · .·.··

=

~ ~ '/'-"'

~

En 't.~$

·~··•ru~--4 .so1ntit)mt

tbf.a

b =14~

"'""""""""'·""· ... ·--

mtr·

•:Jill

l!Jt'{

!i, .

.tl!l

m2

~ smal.l ~p.11Q$at.on of; tbe

tile ~~lie acid t.b.e fnl.lr at.ua·ae1.at.a

in dUute aoluttoos., l..:s

,,.

ara Wilde, vsines of

n;:r

am

lti obtained,

pedualll; n'l"!'!':t~~~~'l tlm true valnesJ'tt ll

wt

ttl.. e1zht

M!f

and r~. U;lus <P~ at'Pl!"Gxl•f.Q& to a straif#.:tt lL~~

and .t'b.e ~~}Jht lSne ¥J'h1c..'ft Ci)Uheeh ftvo Of the total s!gbt

:b~ ~f ·~· log T~ oir ~ t~ pl~

va._ •

.

-i .

-,.y,,.

.0171-.. ~·. ~~ftt ~t.een ~tllt. (4r~1l1B4

·tw

t'mJ ~eth~ Uf;C·ea ·in d~t--~ms .·the.

fh'ts:.t

.t!bswtet.i«l conateDt

aftd .. oth:e: a~~~ a~s~ocktion ~~~t~ fa·

. . - -

-$l'll~ltl by

i~h~25

.~~t

between

tt•

Vl!#~·~"a~ea ~4·

·~ u!SS®i.atlOO L"Q'tl&~t of &CGtiO &Ccf4. Bnd

.... ., ..

~~"''"'1>.

nr

t.iac:tnms and

Et'h•j~etcytaG

a..te . .

mea

~

e:OO'lduet lvl t:f• !tamed alJr:J -~ ... .,...,..

"~•

754

Zit 1Ct•S 'W!liltl Macl:nnae

vam~·

1.75'

x

10•5 •

a~~t"

tbtl

oxalic

moid, th$ $6'0'Gnd .dia$t>C:iQ tloo eO>ncrt~tJt of

pho::~phcu~:to acid at 1

fP

and ·2;:0

c.

valri$$ in P""""''""'

J!!!l;~~·~·"ml'lln~ l'ti values dQt0l."mined bf Jl~a~

-·""'~'.'.lf an 1)l~~oraetr1c tit~tio.n thOd \"11 a oa.l~l.

~1GCtrOI!t~l•

fir$~ diaaoetatltm eonatmlt of' aX&lic acid. 0.01718., ia itl

•

0

0

.

H

H

.

H

0-!

~

r£1

E-1

lfl

<C:C:

of'· ~l!e ada

at

a:?-.

-,o

0.,

,;Oo ....

ptottea••~n•

tlua.t~fi-

Ill

~•Ifl

n:x-

~=t

o ,_ _ _

ttl&.

~l•

_{.··. ...} .dbtatM:I _{. ••...}

at

JrJ,.

_{.·· . . • . . ?+--·} btl'

-~a

.

· -

~:>

o:•1•

a

.

•tltt~ •al~a plcl)tW¢t., · Tilts ftlta D •~•

. . ... ··. . .· ·· ... ·. ·· .. ·.·... ' .. o·

e~

.. •

~n···-~- a_.tO>o 1 ... -~ ¥tt1uo.oJJteb04._d.-·~-.

!i•Oi2

"1'0~•

apeea :teUl?

wall with

Cl1Gttd1·•~"~8"1m

.

l;..-9- ·jt

10-J

a~ VO~

fith .,.,

X·1o•'S.

'qW)~

"

tn e&ktulattng tho dlaeocia tton -~-t &f ~e ttc

ee!rJ.lT~

:fu"hlua1'

f'~~a ~tan aPP2'0ld:~:tt:o!l.

orR.·

0~~~1;.~ tO~ ~·.1•7'

lt ..

10~.

vaa

sutdc~lt.r··

·· .

.to

,"' . . - - , .. -.. , . . . ·, ~<2;_:.:.,;::'···

gl• tbe

~··~u-

ot·at·

.~to.

oalcula,.

val.

Q;f

'""lt.J"'Di!i!i'U

G»n

1l::m~o14 f'otlnd tli5t t~ ap~on.tt.Gfm ~ge.

always saf:fciq.t.,t w'hen caltnt18ting the t{l&eociat!o-n

.0173

rr

₁

v~lue of • .01718 VlilS to-

oo

eh.\m~o tn the ~t ot the aolt:tti-onJ" then in 'L~t;t ftf

ece tic f.!Cid.

&t hsl:f Mtttrali&..ati:Jn of the dibaeic

and ~its.. tl1at i*wi tb the e~pt1$JtJ of' ·il%a.Uo a~M, in

lJhttth·•e$ tT1a ·~t. •~elation is

't.hat

ot a .tat~rl.B e'UotlS

". •·

.

Plt,+pr~

. ·.·

.

· .. ··.·

a~.~d, -~\,. and · ... • _{2 . """} ~ tn fair ae~ri· n

P!ti

+

p!{2

Tna Vt!!lue -·' 2 • .... 1:w

oxaUc

acid at

25°0.,

eale?J.lateil f-rctm t11a resu.lta of

G~ne

nnd InStlld; is

;.21,

¥1'hile t..~e V'~l>-1e obtaLt"led :f'~;>.m. ibe ~asant wg;rk

te

;.01 \Jh.i;ch

{11z:uioo!a'tlon Gf' oxalic acid has baef1; ealenlated betf~en 25~)

-;o

0

_{c ..}

an-d lJ{$tt~een

;o

0 - }5GC..,

by

mesns ;};f the integ~ted

~2

=

;; ',!.,.

""'Ofll.-.. ~

..

=

25

G

c.

and let PlCt ~nd _pK2 be the

values OfpK {the

-

log of the f:1Ctmnd dissoe:lstion tt:>nstant)

eorresponciins; to T2 _{and T1} MspectivelJ,. an.(} at::UltttJte

6.

li

··~.

All . § . .

2~~

·x

;~

.

!;Is

JJJ .

- - 16;,

ttele.

. .

~hat

'th& mes:D

beat

of i011taat1oo

~

t-

~·~M

d'!ssoota .·of oxa'11e aetd

between

2;o ~

;*•

·ts -

165;

aal.m.. ,:, stmi.larly bY'

ttatns

t.tu.t

asme m~ b$tw'l.llen ,ao

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