Catod: qu trnh kh xy ra: cht oxy ho nhn in t cht khAnod: qu trnh oxy ho: cht kh cho in t cht oxy hoChiu dng in trong pin v in phn-++-++

3.3. Phn loi in cc- mch in ha (tt)Chng 3: Pin v in Cc Cc loi in cc (tt)in cc thy tinh: in cc khc: - in cc kh: Kim loi tr tip xc vi kh v ion ca kh- in cc hn hng: Hn hng ca mt kim loi tip xc vi dd cha ion ca kim loi - v d: /C hn hng CadimiDD acid, trung tnh, kim yu:DD kim mnh (pH>12):Dng lm /c ch th o pH

3.3. Phn loi in cc- mch in ha (tt)Chng 3: Pin v in Cc Cc loi mch in haMch ha hc- mch nng : Mch ha hc: pin to thnh do 2 in cc khc nhau v bn cht ha hc.Mch nng : pin to thnh do 2 in cc ging nhau v bn cht ha hc nhng khc v hot ca dd in cc.

Mch c ti- mch khng ti: Mch c ti: dd ca 2 in cc tip xc nhau qua mng xp tn ti th khuch tn.Mch khng ti: dd ca 2 in cc khng tip xc nhau trc tip, v d s dng cu mui, mch kp loi b th khuch tn.

3.3. Phn loi in cc- mch in ha (tt)Chng 3: Pin v in Cc Cc loi mch in ha (tt)Mch thun nghch v khng thun nghch: - S TN v iu kin lm vic: Khi hot ng E ln hn V mt lng v cng nh: tc lm vic v cng chm.

- S TN ca chnh bn thn mch: xy ra theo chiu no ty hiu in th tc ng:Xt pin Jacobi- Daniell:- Nu V > E : mch in phnZn2+ + Cu Zn + Cu2+- Nu V < E : pin in Zn + Cu2+ Zn2+ + Cu pin ny l mch TN.

3.3. Phn loi in cc- mch in ha (tt)Chng 3: Pin v in Cc Cc loi mch in ha (tt)Mch thun nghch v khng thun nghch:(tt) Xt pin : (-) Zn CuSO4 Cu (+)- Nu V > E : mch in phnZn2+ + Cu Zn + Cu2+- Nu V < E : Trong dd khng c Zn2+, nn Cu kt ta ti (-); Cu ha tan ti (+) Cu + Cu2+ Cu2+ + Cu pin ny l mch khng TN.

3.4. in th khuch tn Chng 3: Pin v in CcTn ti trong mch c ti, ti ranh gii tip xc gia hai dd in ccNguyn nhn: do linh khc nhau ca cation, anion xut hin lp in tch kp xut hin bc nhy th in th khuch tnV d: Xt mch: AgNO3 khuch tn t (+) sang (-)

Linh NO3- > linh Ag+ NO3- i qua mng xp nhanh hn bn tri mng xp tch in (-), bn phi tch in (+) kt

Gi tr ca kt khong vi chc mV

t- AgNO3 (a2) t- AgNO3 (a1) (Gii thch?)EF = -G = -t+[cui - u] = t+[(oAgNO3 + RTlna1) - (oAgNO3 + RTlna2)]

Th khuch tn:

3.4. in th khuch tn (tt)Chng 3: Pin v in Cc

Neu t- > t+tc - > +th kt > 0Va Etai > ENeu t- < t+tc - < +th kt < 0Va Etai < ENeu t- = t+tc - = +th kt = 0Va Etai = E

t+ HCl (a1) t+ HCl (a2) (Gii thch?)EF = -G = -t+[cui - u] = t+[(oHCl + RTlna2) - (oHCl + RTlna1)]

Th khuch tn:

Tnh th khuch tn gia 2 dung dch NaCl 0.01N v NaCl 0.001N. Cho h s hot trung bnh ca NaCl 0.01 N l 0.903; NaCl 0.001N l 0.94. Cho linh ca ion Na+ = 43.5 Ohm-1cm2Linh Cl- = 65.5 Ohm-1cm2Tnh th khuch tn ca mch:

Pt, H2|HCl (m = 0.0514) (m = 0.00924) HCl|H2, PtNu linh ca H+ v Cl- bng 315 v 55.5 (tng ng) 18oC. Cho h s hot bng 0.806 i vi dung dch m = 0.0514 v bng 0.906 i vi dung dch c m = 0.00924

Th tiu chun ca Pb2+/Pb l 0.126 VCa Pb, PbSO4, SO42- l -0.355 V. Tnh tch s tan ca PbSO4Xc nh s ti ca Cu2+ trong dung dch CuSO4 long bit rng 25oC, sut in ng ca pin nng c ti bng 0.0268V. H s hot trung bnh ca CuSO4 trong dung dch 0.001m l 0.74; ca dung dch 0.01 m l 0.44

3.4. in th khuch tn (tt)Chng 3: Pin v in Cc Bin php loi tr kt - Dng cu mui: dd m c ca mt mui c linh cation v anion gn bng nhau trong dd keo aga. VD: KCl, KNO3, NH4Cl, NH4NO3, .. kt khng ng k. - To mch kp: Loi b hon ton kt (-) Ag,AgCl HCl(a)H2, Pt, H2 HCl(a) AgCl,Ag (+)

3.5. ng dng ca php o sc in ng (S)Chng 3: Pin v in Cc Phng php o SEw: pin mu c S bit, n nh, bn vi thi gian pin Westonpin Weston: (-) /C hn hng Cadimi(+) /C thy ngn loi 2

3.5. ng dng ca php o sc in ng (S)Chng 3: Pin v in Cc ng dng o pHNguyn tc:

o S ca pin gm:

in cc c bit: in cc Calomel, in cc bc

in cc c ph thuc pH ca dd in cc ch th: in cc Hydro, in cc quinhydron, in cc thy tinh

3.5. ng dng ca php o sc in ng (S) (tt)Chng 3: Pin v in Cc ng dng o pH (tt)(-)Hg, Hg2Cl2 | KCl || H+ (x)| ien cc thuy tinh (+)u iem: khong dung phu gia kem theo.Nhc iem: de v v mang thuy tinh mong 0,01 0,03mm.

3.5. ng dng ca php o sc in ng (S) (tt)Chng 3: Pin v in Cc ng dng Xc nh h s hot trung bnh ()V d: Xc inh ca dd HCl nng mLp pin: (-) Pt, H2 (1 atm) | HCl (m) | Hg2Cl2, Hg (+)Phn ng:Hg2Cl2 + H2 = 2Hg + 2HCl

Sc in ng:

3.5. ng dng ca php o sc in ng (S) (tt)Chng 3: Pin v in Cc ng dng Xc nh h s hot trung bnh () (tt)- Nu bit Eo : o E, xc inh - Nu cha bit Eo : bin i (*) thnh: (*)=YKhi m 0 : 1 nn Y Eo V th Y-m , ngoai suy ti m= 0 thu c Eo

3.5. ng dng ca php o sc in ng (S) (tt)Chng 3: Pin v in Cc ng dng Xc nh tch s tan (T)V d: xc inh T ca AgCl Lp pin: (-) Ag, AgCl | HCl | Cl2, Pt (+) Phn ng:Ta li c:Nn:

3.6. Ngun in ha hcChng 3: Pin v in Cc Ngun in s cp- pin: ch dng mt ln.V d: pin kh La Clanch (Zn-C) Ngun in th cp- acquy: C th np in v s dng nhiu lnV d: Acquy acid, acquy kim Pin nhin liu: lm vic lin tc, trc tip bin ha nng thnh in nngV d: pin Hydro-oxyPin nhin liuPin La-Clanch