Chng 12IN HA HC

Cu2+ (dd) + Zn(r) Cu(r) + Zn2+ (dd) Zn - 2e- Zn2++200+2Cu 2+ + 2e- Cu

Cht oxyhoCht b khCht khCht b oxyhoOXH1 + ne KH1KH2 - ne OXH2Qu trnh khin cc : CatodQu trnh oxyhoin cc : AnodOXH1 + KH2 KH1 + OXH2Dng OXHlh c tnh OXHDng KHlh c tnh kh

Cc loi phn ng oxyho khPhn ng gia cht OXH khc cht KH 2Ag+(dd) + Cu 2Ag + Cu2+

Phn ng oxyho kh ni phn t AgNO3 (r) Ag (r) + NO (k) + O2(k)Phn ng t oxyho kh (p d phn )Cl2 (k) + H2O (l) HClO (dd) + HCl (dd)

Cn bng phn ng oxy ha - kh.Nguyn tc chung:Bo ton: in tch , in t, nguyn t.

Nu dng KH v dng OXH c s oxy khc nhau s c s tham gia ca mi trng Mi trng axit : d oxy + 2H+ = thiu oxy + H2OMi trng trung tnh: d oxy + H2O = thiu oxy + 2OH- thiu oxy + H2O = d oxy + 2H+Mi trng kim : d oxy + H2O = thiu oxy + 2OH-

Cch tin hnh phn ng oxyho khTrc tip - cht OXH tip xc KH Ho nng p nhit nng Gin tip cht OXH khng tip xc trc tip vi cht KHHa nng p in nng Cu(s) + 2 Ag+(aq) ---> Cu 2+(aq) + 2Ag(s)

G < 0

Ti sao phi nghin cu in ho hc?Pinn mnCng nghip ho cht sn xut:Cl2, NaOH, F2 v AlP oxh sinh hcThe heme group

Th in cc Mn+ (dd) + ne M in cc kim loi M |Mn+G = - nF- th in cc th kh cng dng Mn+ c tnh oxyho cng mnh M c tnh kh cng yu cng m M c tnh kh cng mnh Mn+ c tnh oxyho cng yu+++---___+++ Cu2+/CuZn2+/Zn 0(Zn2+/Zn) < 0 (Cu2+/Cu)0 - th in cc tiu chun th kh chunS e trn thanh Zn nhiu hn thanh ng

CU TO V HOT NG NGUYN T GANVANICZn2+ +2e ZnCu2+ +2e CuSO42-Zn2+

CU TO V HOT NG NGUYN T GANVANIC(-) Zn | Zn2+ (dd) || Cu2+(dd) | Cu (+)(-) M1| M1n+|| M2n+| M2 (+)

Qu trnh kh Catod(+)Qu trnh oxyhoAnod (-)- < +Zn -2e Zn2+Cu2+ +2e Cu

Cc loi in cca. in cc kim loi.d. in cc oxy ha - kh.b. in cc kim loi ph muic. in cc khAgAgCl Cl-Pt H2 H+Pt Fe2+, Fe3+Zn Zn2+Zn2+ +2e ZnAgCl +1e Ag + Cl-2H+ +2e H2Fe3+ +1e Fe2+

Epin = + - - = Cu - Zn

in cc Hydro tiu chunPt | H2 | H+0H+/ H2 = 0 aH+ =1mol/l ; PH2 =1atm

Cch xc nh th in cc Th in cc ca mt in cc bt k bng th hiu ca n so vi in cc Hydro tiu chun.E0 = 0c - 0 hydro E0 = 0c

0 ( Cu2+/Cu) = 0,34V

0( Zn2+/Zn) = - 0,76V

Th in cc tiu chun 250CEOS

Phn loi cc cht oxy ho kh

Sc in ng ca nguyn t GanvanicaKH1 + bOXH2 cOXH1 + dKH2G = - Amax = -qE =-n (e.NA)E = -nFE (thun nghch) G0 = -nFE0 +ne-nee = 1,6.10-19 [C]NA= 6,02.1023F = 96500 [C/mol]G [J]R= 8,314 [J/mol.K]E [v] ; E0[v] 250C

Quan h gia hng s cn bng v sc in ng tiu chunF = 96500[C/mol]R=8,314 [J/mol.K]T [K]Ln = 2,303.lgE0 [v] 250C

Phng trnh Nernst. a OXH + ne + x[MToxh] b KH + y[MTkh] G = -nF ; G0 = -nF0

Th in cc ( th kh ) l thng s cng . 250C

Th in cc ph thuc :

a OXH + ne + x[MToxh] b KH + y[MTkh]Bn cht cp OXH/KH v bn cht dung miNng cht OXH v cht KHNhit Mi trng nh hng cht to phc v to kt ta

[KH] tnh oxh ca OXH tnh kh ca KH

OXH + . Phc hay kt ta [OXH] tnh oxh ca OXH tnh kh ca KH KH + . Phc hay kt ta [KH] tnh oxh ca OXH tnh kh ca KH

[OXH] tnh oxh ca OXH tnh kh ca KH

Th kh v th oxyhoQu trnh kh: OXH + ne KH G = -nF(kh)Qu trnh oxyho: KH - ne OXHG = -nF(oxh)

G = - G (oxh) = - (kh)

Chiu ca phn ng oxy ha - kh.OXH1 + ne KH1 G1 = -nF1KH1 - ne OXH1 G1 = -nF (- 1)OXH2 + ne KH2 G2 = -nF2KH1 + OXH2 OXH1 + KH2 G < 0 G = G1+ G2= -nFE = -nF(2 - 1) < 02 - 1 > 0 ; 2 > 1OXH > + KH < KH > + OXH

PIN NNG

(-)Cu| Cu2+; 0,1M || 1,0M ; Cu2+ |Cu (+) 250C

in phn Zn(r) + Cu2+(dd) Zn2+(dd) + Cu (r) in phn G>0Pin G < 0Phn ng ho hc Dng inPin G < 0in phn G>0

Cc qu trnh xy ra trong Pin v bnh in phn ngc nhau Cc dngCc mCatod in phn AnodZn2+ +2e Zn Cu -2e Cu2+ Anod Pin CatodZn -2e Zn2+ Cu2+ +2e Cu

Th phn gii Ep th hiu ti thiu tin hnh qu trnh in phnQu th- 0 = Ep Epin = a0 + c 0 0 ph thuc vo bn cht in cc, mt dng in, thnh phn dd.Ep = a0 + c 0 + Epin = a0 + c 0 + + - -Ep = (+ + a0 ) - (- - c0 )Th phng in anodTh phng in catod

S in phn trong dd in lyCatod (-) /qt kh (Mn+/M) > (H2O /H2)(- - c0) ln OXH p.inMn+ +ne M pH < 7 2H3O+ +2e H2+ 2H2OpH 72H2O +2e H2+ 2OH- (Mn+/M) < (H2O /H2) Anod (+) / qu trnh oxyho( + a0 ) nh KH s phng in Anod tr (graphit)Anion khng cha oxy: I-, Br-, Cl-..Nc 4OH- - 4e O2+2H2O pH>7 2H2O - 4e O2 + 4H+ pH7Anion c oxyAnod tan (kim loi)M ne Mn+ (Mn+/M) <

nh lut Faradaym lng cht to thnh hay ho tan in cc ng lng gam cht Q- lng in i qua cht in ly ; Q = I.tn s electron trao iI cng dng in ; t- thi gian