Title Electro Chemistry Engg. Practice Sheet_With Solve-25.pdf ✅

2 ....................................................................................................................................  Chemistry 2nd Paper Chapter-4 Rhombus Publications 7. wRsK †K¬vivBW e ̈vUvwi‡Z wb‡¤œi †Kvl wewμqv Øviv we`y ̈r Drcbœ nq- Zn(s) + Cl2(g)  ZnCl2(aq) cÖgvY gy3kw3i cwieZ©b (G 0 ) †ei Ki| cÖgvY weRviY wefe: E 0 Zn++/Zn = – 0.76 V and E0 Cl2 /Cl – = 1.36 V [BUET 18-19] mgvavb: E 0 cell = 0.76 + 1.36 = 2.12 V G 0 = – nF E0 cell = – 2 × 96500 × 2.12 J mol–1 = – 409160 J mol–1 = – 409.16 kJ mol–1 8. Au ZworØv‡ii ga ̈ w`‡q AuCl – 4 Avq‡bi `ae‡Y AcwieZ©bxq Zwor cÖevwnZ Kiv nj| 10 wgwbU ci K ̈v‡_v‡Wi fi 1.314 gm e„w× †c‡j Zwor cÖev‡ni gvb wbY©q Ki| (Au Gi cvigvYweK fi = 197) [BUET 17-18] mgvavb: Au3+ + 3e–  Au I = neF t = 1.314 197  3  96500 10  60 = 3.22 A 9. GKwU †jvnvi wUDe‡K wRsK w`‡q cÖ‡jc w`‡Z n‡e| G m¤úwK©Z wb‡Pi cÖkœ ̧‡jvi DËi `vI| (a) †Kvb avZz K ̈v‡_vW wn‡m‡e e ̈envi Ki‡Z n‡e? (b) †Kvb avZz A ̈v‡bvW wn‡m‡e e ̈envi Ki‡Z n‡e? (c) †Kvb B‡jK‡UavW †_‡K ewnt ̄’ mvwK©‡U B‡jKUab cÖevwnZ n‡e? (d) A ̈v‡bvW-G msNwUZ B‡jK‡UavW wewμqvwU wjL| (e) K ̈v‡_vW-G msNwUZ B‡jK‡UavW wewμqvwU wjL| [BUET 16-17] mgvavb: (a) †jvnvi wUDe K ̈v‡_vW wn‡m‡e e ̈envi Ki‡Z n‡e| (b) wR1⁄4 A ̈v‡bvW wn‡m‡e e ̈envi Ki‡Z n‡e| (c) A ̈v‡bvW †_‡K ewnt ̄’ mvwK©‡U B‡jKUab cÖevwnZ n‡e| (d) A ̈v‡bv‡W RviY: Zn(s)  Zn2+(aq) + 2e– (e) K ̈v‡_v‡W weRviY: Zn2+(aq) + 2e–  Zn(s) 10. wb‡Pi wewμqvwU 298 K ZvcgvÎvq ̄^ZtùzZ© wK bv Zv wbY©q Ki: Co(s) + Fe2+(aq)  Co2+(aq) + Fe(s) †`Iqv Av‡Q, [Co2+] = 0.15 M; [Fe2+] = 0.68 M; E 0 Co2+/Co = – 0.28 V; E0 Fe2+/Fe = – 0.44 V [BUET 16-17] mgvavb: E 0 cell = Eanode(Ox) + Ecathode(Red) = 0.28 – 0.44 = – 0.16 V Ecell = E0 cell + 2.303  RT 2F log [Fe2+] [Co2+] = – 0.16 + 0.0592 2 log 0.68 0.15 = – 0.14 V  wewμqvwU ̄^Ztù~Z© bv| 11. Zn/Zn2+ || Cu2+/Cu, EMF KZ n‡e Zv wnmve Ki| G‡ÿ‡Î Zn2+ Gi NbgvÎv 0.10 mol L–1 Ges Cu2+ Gi NbgvÎv 0.05 mol L–1 | 298 K ZvcgvÎvq E 0 Zn/Zn2+ = 0.70 V Ges E 0 Cu/Cu2+ = – 0.34 V| [BUET 15-16] mgvavb: †Kvl wewμqv: Zn(s) + Cu2+(aq)  Zn2+ (aq) + Cu(s) Ecell = E0 cell + 2.303 RT eF log [Cu2+] [Zn2+] = E0 Cu2+/Cu – E 0 Zn2+/Zn + 2.303 RT eF log [Cu2+] [Zn2+] = 0.34 – (– 0.70) + 2.303  8.316  298 2  96500 log 0.05 0.10 = 1.04 + 0.02955  log 0.5 = 1.04 + 0.02955 – 0.301) = 1.04 – 0.0088895 = 1.0311 V 12. wb‡¤œi Zwor ivmvqwbK †Kvlmg~‡ni Aa©‡Kvl wewμqv I mvgwMÖK †Kvl wewμqv †`LvI| (a) Zn / Zn++(aq) | Cl – (aq), Hg2Cl2(s)/Hg (b) Pb/PbSO4(s), H2SO4(aq) | PbO2/ Pb [BUET 14-15] mgvavb: (a) Aa©‡Kvl wewμqv: A ̈v‡bv‡W RviY: Zn  Zn2+ + 2e– K ̈v‡_v‡W weRviY: Hg2Cl2 + 2e–  2Hg + 2Cl – mvgwMÖK †Kvl wewμqv: Zn + Hg2Cl2  2Hg + Zn2+ + 2Cl – (b) Aa©‡Kvl wewμqv: A ̈v‡bv‡W RviY: Pb + H2SO4  PbSO4 + 2e– + 2H+ K ̈v‡_v‡W weRviY: PbO2 + 4H+ +SO2– 4 + 2e–  PbSO4 + 2H2O mvgwMÖK †Kvl wewμqv: Pb + 2H2SO4 + PbO2  2PbSO4 + 2H2O 13. GKwU ZworØv‡i 0.2 mol/dm3 NbgvÎvi HCl Gi Rjxq `aeY e ̈envi Kiv nj| 27C ZvcgvÎvq ZworØviwUi RviY wefe wbY©q Ki| [BUET 13-14] mgvavb: EH = E H – RT F ln [H+ ] GLv‡b, E  H  EH = – 8.314  (273 + 27) 96500  ln [0.2  1] = 0.0416 V 14. 27C ZvcgvÎvq GKwU ZworØv‡i 0.02 mol dm–3 HCl Gi `aeY e ̈envi Kiv nj| ZworØviwUi RviY wefe wbY©q Ki| [BUET 12-13] mgvavb: RviY wewμqv: 1 2 H2 – e –  H + ; E 0 cell = 0 V, n = 1, T = 300 K Ecell = E0 cell – RT eF ln [H+ ] = 0 – 8.314  300 1  96500 ln [0.02] = 0.1011 V