2-2-2 Preparations F-：CaF2,fluorite萤石Na3AlF。cryolite冰晶石; Cl-/ Br: seawaterI-: algae; NaIO16
16 2-2-2 Preparations ◼ F - : CaF2 , fluorite萤石; Na3AlF6 cryolite冰晶石; ◼ Cl- / Br- : seawater ◼ I - : algae; NaIO3
F22F--2e-=FAnode(graphite):Φ(F,/F)=2.87VCathode(Cu-Ni alloy):2H++2e=HΦF2/HF(aq.)=3.06VElectrolysis reaction:2HF=F,+H阴极阳极3NHF2HFH+H
17 阴极 阳极 3NHF2 2HF H+ F－ Anode(graphite)： 2F - - 2e－ = F2 Cathode(Cu-Ni alloy)：2H+ + 2e = H2 Electrolysis reaction： 2HF = F2 + H2 F2 : º(F2 /F- ) = 2.87V ºF2 /HF(aq.) = 3.06V
In 1886, Moissan electrolysis method.In 1986, Christe devised to prepare F2 by chemical method2KMn0,+2KF+10HF+3H,0=2K,MnF.+8H,0+30SbCl+5HF=SbF-+5HCIK,MnF,+2SbF,= 2KSbF+ MnF4 (150℃)MnF,=MnF,+1/2F,K,PbF.=K,PbF+F,（heat)BrFs(g)= BrF3(g) + F2(g) (heat)18
18 2KMnO4 + 2KF + 10HF + 3H2O = 2K2MnF6+ 8H2O + 3O2 SbCl5 + 5HF = SbF5 + 5HCl K2MnF6 + 2SbF5 = 2KSbF6 + MnF4 （150℃） MnF4 = MnF3 + 1/2F2 K2PbF6 = K2PbF4 + F2 （heat） BrF5 (g) = BrF3 (g) + F2 (g) （heat） In 1886，Moissan electrolysis method. In 1986，Christe devised to prepare F2 by chemical method
Cl : β℃i2/ci = 1.36V2+= 1.51V, βMn02/Mn2+=1.23V?MnO4-/MnIn labKMnO(s) + HCI (conc.) → Mn2+ + Cl, +K+ + H,OMnO,(s) + HCI (conc.) → Mn2+ + Cl, +K++ H,OK,Cr,O, + HCI (conc.) → Cr3+ + Cl + H,O (heat)InNaCI +H,O → NaOH + Cl(g)+H2(g)industryAnode（graphite） : 2CI-2e-=Cl,Cathode (Iron net) : 2H,0+ 2e-=H, +20H19
19 Cl2 : º Cl2/Cl = 1.36V º MnO4-/Mn 2+ = 1.51V, º MnO2/Mn 2+ = 1.23V KMnO4 (s) + HCl (conc.) → Mn2+ + Cl2 +K+ + H2O MnO2 (s) + HCl (conc.) → Mn2+ + Cl2 +K++ H2O K2Cr2O7 + HCl (conc.) → Cr3+ + Cl2 + H2O (heat) NaCl + H2O → NaOH + Cl2 (g)+ H2 (g) Anode（graphite）：2Cl- - 2e－ = Cl2 Cathode（Iron net）：2H2O + 2e- = H2 + 2OHIn lab In industry
Br2seawater/salt water,pH =3.5Inindustry氯氧化;空气吹出;Na,CO(aq.)吸收;H,SO4脱水Br- + Cl → Br2(g) +2CI (383K)3Br2 +3CO32- = 5Br + BrO3- + 3CO,Br + BrO3- + 6H+ → Br2(l)+ 3H,0In labNaBr + Cl → Br2 + NaCI20
20 Br2 seawater/salt water , pH = 3.5 氯氧化;空气吹出;Na2CO3 (aq.)吸收;H2SO4脱水 Br－ + Cl2 → Br2 (g) + 2Cl- （383K） 3Br2 + 3CO3 2- = 5Br- + BrO3 - + 3CO2 Br- + BrO3 - + 6H+ → Br2 (l)+ 3H2O NaBr + Cl2 → Br2 + NaCl In industry In lab