Tdeusz Górecki Ionic Equiliri Acid-Bse Equiliri Brønsted-Lory: n cid is proton, se is. Acid Bse ( 3 PO 4, O), ( N 4 ) nd ( PO - 4 ) cn ll ehve s cids. Exmple: 4 N N3 Sustnces hich cn ehve oth s cids nd s ses:, or sustnces (e.g. O, S - ). S cid S se S se cid Free protons in ny solvent, thus the ove rections re. In relity: 4 N O N3 3O Energy required to dissocite to nd : kcl/mol S Pge
Tdeusz Górecki Ionic Equiliri Equilirium constnt for : A 3 O O A A A : O B O B Reltionship eteen nd : B O B Leis: n cid is n ; se is n. Strength of cids nd ses SO 4 O 3O SO4 O O O O 3 3 3 N 3 O O N cid 1 se cid se1 O SO SO 3 4 4 O O O 3 Pge 1 3 3
Tdeusz Górecki Ionic Equiliri 3 O N N vlue of mens tht the cid is, thus: of ter: O O Equilirium constnt using : Activity of ter is y thermodynmic convention proportionl to the of ter in the solution. In dilute solutions it is close to. Activity of ter cn e : O O γ O γ O " " constnt: O O / γ γ γ γ Pge
Tdeusz Górecki Ionic Equiliri At 5, p, nd the neutrl point is p. At 5 in 3 M NlO 4 p, nd the neutrl point is p. Pge 3
Tdeusz Górecki Ionic Equiliri solvents: At -6, the equilirium constnt is: N3 N N N 3 4 3 4 1 N N Thus, the p scle (defined s -logn 4 ) in liquid mmoni rnges from _ to. p of strong cid Initilly P, or " ", defined s P -log Tody's definition of p: p p log log( γ ) Generl pproch Exmple: l Mss lnce: Ion product of ter: l O hrge lnce: O l Solution: A This is qudrtic eqution, hich pplies. When, (O - is ) At higher ionic strength, ctivity coefficient should e used. Pge 4
Tdeusz Górecki Ionic Equiliri Strong se: Exmple: NO Mss lnce: Ion product of ter: hrge lnce: N 14 O 1 Solution: Bsic solution, thus, nd in generl Exmple: p of 7 1 M solution of NO 4 8 4.14 1 mol / L p Simplified eqution: p Pge 5
Tdeusz Górecki Ionic Equiliri p of strong cid/se s function of concentrtion: log -1 - -3-4 -5-6 -7-8 -9-1 4 6 8 1 1 14 log (cid) p log (se) Mixture of strong cid nd strong se Exmple: l nd NO Mss lnce: l Mss lnce: N 14 Ion product of ter: O 1 hrge lnce: N l O When the cid nd the se re : O 1 mol / L 7 Pge 6
Tdeusz Górecki Ionic Equiliri Titrtion of Strong Acids nd Bses olume of the system chnges, thus must e tken into mss lnces rther thn. Exmple: titrtion of l ith NO: Mss lnce: l ( ) Mss lnce: N ( ) 14 Ion product of ter: O 1 hrge lnce: N l O At the equivlence point, (1:1 stoichiometry) nd Before the equivlence point, : After the equivlence point, : ( ) Pge 7
Tdeusz Górecki Ionic Equiliri Pge 8 In the vicinity of the equivlence point (.1 M, 5 ml,. M): 5 6 7 8 9 4.999 4.9995 5 5.5 5.1 p O- neglected Full eqution neglected Plotting the titrtion curve titrted ith : / / Titrtion of ith : / /
Tdeusz Górecki Ionic Equiliri Exmple: Titrtion curve 14 1 1 8 p 6 4 4 6 8 1 1 14 16 18 4 6 8 3 3 34 36 38 4 4 44 46 48 5 titrtion: l titrted ith NO Λ λ λ N N λ O O λ l l 1 1 Λ - conductnce ( k Ω cm ) λ - conductnce. X At 5, conductnces λ re: Procedure: the vlues of p; λ N λ O λ l λ Pge 9
Tdeusz Górecki Ionic Equiliri nd O - ; clculte from the eqution; clculte N /( ) (from ); clculte l /( ) (from ). 5 ml.1 M l titrted ith. M NO: 35 3 5 onductnce 15 1 5 1 3 4 5 5 ml.1 M l titrted ith.1 M NO:.11.15.1.95 onductnce.9.85.8.75.7.65.6 4 5 6 Pge 3
Tdeusz Górecki Ionic Equiliri Titrtion error Titrtion error ep ep - t ' - t Titrtion of 5 ml.1 M l ith. M NO: ' ' Enlrged section (end point detected ith t p 5): Pge 31
Tdeusz Górecki Ionic Equiliri Titrtion error: 4.9963 5 1 5 5 ml.1 M l titrted ith.1 M NO: Titrtion error: 4 5 1 5 Grn plots Titrtion of ith : Before the equivlence point, is negligily smll, thus: ( ) Pge 3
Tdeusz Górecki Ionic Equiliri or f 1 ( )1 p, nd re, thus plot of f 1 s function of should e ith slope of intersecting the X xis t the,. Exmple: 5 ml.1 M l titrted ith. M NO:.5.45.4.35.3 f1.5..15.1.5 3 4 5 6 7 ml In the vicinity of the equivlence point:.1.9.8.7.6 f1.5.4.3..1 4.5 4.6 4.7 4.8 4.9 5 5.1 5. 5.3 Pge 33
Tdeusz Górecki Ionic Equiliri Wek monoprotic cids nd ses A A A A O B O B B O B p p p Pge 34
Tdeusz Górecki Ionic Equiliri N 4 : N 3 : Dependence of on : A A γ p p log γ γ log γ γ γ γ γ logγ Using nd setting logγ I (ctivity coefficient for n ): I p 4.757.51 ' I I I 1 here ' is the (usully.). Pge 35
Tdeusz Górecki Ionic Equiliri Best fit: Temperture dependence of p : Pge 36
Tdeusz Górecki Ionic Equiliri Pge 37 lculting the p of ek cid non: Unknon: A A O Mss lnce: A A A hrge lnce: O A A A A A A 1 A A From : A A From : O Sustituting nd into : A Thus: ) ( 3 A
Tdeusz Górecki Ionic Equiliri Simplifying ssumption: is negligily smll A A When : A A A Flood's digrm From nd : A Flood's digrm p 4 6 8 - log -4-6 Strong cid p4.75 p7.53 p1.7-8 Pge 38
Tdeusz Górecki Ionic Equiliri Degree of dissocition A A Degree of : α Degree of : A A A A A A A A 1 α A A A A Degree of dissocition nd formtion 1.8.6.4. degree of formtion degree of dissocition 4 6 8 1 1 14 p Pge 39
Tdeusz Górecki Ionic Equiliri Sillén's digrm (, ) Acetic cid,.1 M, p 4.75-4 6 8 1 1 14 A - -4 log -6-8 -1 A -1-14 O - p 1. is determined from the : log p. O - is determined from : log O log p p 3. A - is determined from nd : A A 4. A is determined from nd : A A Pge 4
Tdeusz Górecki Ionic Equiliri p of given system cn e determined from the : A O Acidic solution, thus cn e neglected A Solution for the proton condition cn e esily found on equilirium digrms using the : log ( A O ) Acetic cid, M, p - 4 6 8 1 1 14 A - -4 Pointer log -6-8 3.4 A -1-1 O - -14 p Pge 41
Tdeusz Górecki Ionic Equiliri Acetic cid, M, p 4 6 8 1 1 14 - O - -4-6 -8 A Pointer A - -1 6.8-1 -14 Plotting equilirium digrms 1. nd O - : lines t (slopes of nd, respectively). A - : for A A A A log A log p A p d log A dp 1 for A A Pge 4
Tdeusz Górecki Ionic Equiliri 3. A: for A A A A for A A log A log p A p d log A dp 1 4. When : A A A log A log A log Wht is the p of.1 M NAc? :, thus : A log A A O A O log log A.3 Pge 43
Tdeusz Górecki Ionic Equiliri - -4 log oncentrtion M -6-8 -1-1 -14 4 6 8 1 1 14 p Pge 44
Tdeusz Górecki Ionic Equiliri Wht hppens hen the cid concentrtion is?.1 M F, p 3.17 Proton condition: F O F 4 6 8 1 1 14 - O - log -4-6 -8 F F - -1-1 -14 p Pge 45
Tdeusz Górecki Ionic Equiliri - 4 6 8 1 1 14 O - log -4-6 -8 F F - Pointer p3.6-1 -1-14 p hecking the results: p O - F 3.6 F 1 1 3.34 F 1 3.6 Mss lnce: F F 1 1 3.6 3. 34 Algeric solution: A p Pge 46
Tdeusz Górecki Ionic Equiliri Lo concentrtions of very ek cids: 5 x 1-5 M N, p 9.3 4 6 8 1 1 14 - O - -4 N N - log -6-8 N - O - -1-1 -14 p Mixture of cids Strong cids represented y. Strong ses represented y. Typiclly on Equiligrps. Ech or represented y the expressions: A A B B p found t the point here. Pge 47
Tdeusz Górecki Ionic Equiliri.1 M Ac ( 1-4.75 ) nd.1 M Fo ( 1-3.75 ) 4 6 8 1 1 14 - Ac Ac - -4 Fo Fo - log -6-8 Ac - Fo - O - -1-1 -14 O - p Proton condition: Pointer function: log - -4-6 -8 4 6 8 1 1 14 Ac Pointer p3.3 Ac - Fo Fo - -1-1 O - -14 p Pge 48
Tdeusz Górecki Ionic Equiliri Pge 49 Assumptions: negligily smll f f f f f f Itertion: f f f irculr reference: f f f Mixture of strong nd ek cid:.1 M l nd.1 M Ac O l Ac l l Solution: p
Tdeusz Górecki Ionic Equiliri - -4 4 6 8 1 1 14 Ac - l - log -6-8 Ac - l - O - Ac -1-1 -14 O - p Slt of ek cid nd ek se To independent linked y the condition tht they hve the sme. A 1 A B B O lnces: A A B B lnce: B A O : A O B Pge 5
Tdeusz Górecki Ionic Equiliri If nd O - : 1 1 1 p on (provided the ssumption ove is fulfilled)! Exmple: p of.1 M N 4 Ac (p 1 4.75, p 9.5) p / ( p p ) 1 1 The vlue of is coincidentl. Equilirium digrm: 4 6 8 1 1 14 - -4-6 Ac - N 4 log -8 N 3 Ac -1-1 O - -14 p Pge 51
Tdeusz Górecki Ionic Equiliri Pointer function: 4 6 8 1 1 14 - -4 Ac - N 4 log -6-8 N 3 Ac -1-1 -14 O - Pointer p7 p Full solution: eqution in. 1 The eqution is, thus: 1 1 1 Pge 5
Tdeusz Górecki Ionic Equiliri Exmple: Dimethylmmonium cette p 1 4.75 ( ), p 1.76 ( ) 7.8 7.7 p 7.755 7.6 7.5 p 7.4 7.3 7. 7.1 7 4 6 8 -log Generl eqution for the titrtion curve lnce: lnce: A A N A A lnce: N A O Pge 53
Tdeusz Górecki Ionic Equiliri Pge 54 A or A α A α Titrtion of ith : Simplifying ssumptions: efore the equivlence point ; fter the equivlence point
Tdeusz Górecki Ionic Equiliri Exmple: titrtion of 1 ml.1 M Ac ith.1 M NO 14 1 1 p 8 6 4 4 6 8 1 1 14 ( p ) ( ) ( p ) ( ) End point determined y the of the. If necessry, cn e otined in the sme mnner. : 14 1 1 p 8 6 4 d(p)/d 4 6 8 1 1 14 Pge 55
Tdeusz Górecki Ionic Equiliri nd : 14 1 1 8 6 4-9.9 9.95 1. 1.5 1.1-4 -6-8 Another y to plot the titrtion curve: through Φ: Sustitution to the generl eqution: Φ Φ ( ) Itertion set nd get the Pge 56
Tdeusz Górecki Ionic Equiliri 14 1 1 p 8 6 4 1 Frction titrted solution: Φ O α O 1 14 1 1 p 8 6 4 1 Frction titrted Pge 57
Tdeusz Górecki Ionic Equiliri The plot of enles esy comprisons of different. Exmples: Different of the cid 14 14 1 1 1 1 p 8 6 p 8 6 4 4 1 ml 1 Frction titrted ml 3 ml 5 1 15 5 3 35 4 Different vlues 14 14 1 1 1 1 8 8 p 6.1 M p 6.1 M 4 1e-6 4 1e-6 1e-5 1e-4 1e-5 1e-4 1 Frction titrted 5 1 15 Pge 58
Tdeusz Górecki Ionic Equiliri Different : 14 14 1 1 1 1 p 8 6 4 p 4.75.1 M.1 M.1 M.1M 1 Frction titrted p 8 6 4 p 4.75.1 M.1 M.1 M.1 M 5 1 15 Different concentrtions of the : 14 14 1 1 1 1 p 8 6 4 p 4.75.1 M.1 M.1 M.1 M 1 Frction titrted p 8 6 4 p 4.75.1 M.1 M.1 M.1 M 5 1 15 Pge 59
Tdeusz Górecki Ionic Equiliri Titrtion of ith : α B α A Φ α α A B O O here B α ; B B B α A A A A A 14 1 1 p 4.75 p 5.1 M 14 1 1 p 4.75 p 5.1 M 1 ml p 8 6 p 8 6 4 Strong se 5 1 Frction titrted 4 Strong se 5 5 1 15 Pge 6
Tdeusz Górecki Ionic Equiliri Pge 61 Titrtion error At the equivlence point ' here is t the ' Titrtion error: 1 1 1 1 ' ' '.. Φ ep ep ep ep ep e T At the equivlence point nd its vicinity: Also, ner the equivlence point,, thus 1 1 α Φ ) ( 1 1 ep α ep ) ( 1 Φ ep ep ep ep ) ( 1 Φ
Tdeusz Górecki Ionic Equiliri Exmple:.1 M Ac,.1 M NO, p ep insted of p t the equivlence point Φ ep 1 ()(1 6 1 8 1 ) 1 8 4.75 Titrtion of ek se ith strong cid: Φ ep ( ) 1 ep ep ep Pge 6