X2 oxidization ability: Example: C2+Br→2C+Br2
Cl2+Br- 2Cl-+Br2 X2 oxidization ability： Example:
reacts with water:two types of reactions Oxidization reaction:X,+2H,O->4HX+O, F2(vigorous)>Cl2(slow under light)>Br(extremely slow) Disproportionation reaction(without base): X,+H,O-HXO+HX Cl2 Br2 I2 Ke(C12)=4.2×10-4 K8(Br2)=7.2×10-9 KeL2)=2.0×10-13 We can see that the major constituent of the solution dissolved with Cl,Br2 and I,is their elemental substance, respectively..氯水，溴水，碘水的主要成分是单质。 Presence of a base can promote dissolution and dispropor- tionation reaction在碱存在下，促进X2在H,0中的溶解、歧化
X2 + 2H2O ⎯⎯→4HX + O2 Disproportionation reaction(without base)： 2 2 2 Cl > Br > I We can see that the major constituent of the solution dissolved with Cl2, Br2 and I2 is their elemental substance, respectively.氯水, 溴水, 碘水的主要成分是单质。 Presence of a base can promote dissolution and disproportionation reaction 在碱存在下，促进X2在H2O中的溶解、歧化。 • reacts with water：two types of reactions Oxidization reaction： 4 (Cl2 ) 4.2 10− K = × 9 (Br2 ) 7.2 10− K = × 13 (I2 ) 2.0 10− K = × X2 + H2O HXO + HX F2(vigorous) > Cl2 (slow under light) > Br(extremely slow) I2
Products of disproportionation reaction under basic condition X2+20H→X+X0+HO 30X→2X+X03 3X2+60H→5X+XO3+3H,0 0.7665 BrO 0.5357 0.4556 1.0774 BrO B Br 0.5196
Products of disproportionation reaction under basic condition + ⎯⎯→ + + + ⎯⎯→ + + − − − − − 3X 6OH 5X XO 3H O X 2OH X XO H O 2 3 2 2 2 _ 3OX - → 2X - + XO 3 -
room low heated temperature temperature Cl2 C103 CIO CIO PH>4 Br2 BrO: BrO3BrO(0°C)PH>6 I03 I03 PH>9
room temperature heated low temperature I PH > 9 2 −3 IO −3 IO −3 IO Br PH > 6 2 − BrO3 − BrO3 BrO (0 C) − O Cl2 ClO PH > 4 3- − ClO ClO-
3.The preparation of the elemental substances F2(g)electrolysis: The formal reaction:2KHF2 电解)2KF+H2+F + HF The real reaction 2HFFH2 C1,(g)Industry method (electrolysis): 2NaC1+2H,0地解>H2+Cl2+2NaOH √Laboratory method: MnO +4HCH A >MnCl,+Cl(g)+2HO (concentrated)
•Cl2 (g) 2NaCl 2H O H2 Cl2 2NaOH 电解 + 2 ⎯⎯→ + + 9Laboratory method： MnO2 +4HCl⎯⎯→MnCl2+Cl2 (g)+2H2O Δ 9Industry method (electrolysis)： 3. The preparation of the elemental substances ： (concentrated) •F2 (g) electrolysis： 2 2 电解 2KHF2⎯⎯→2KF+H +F + HF The real reaction 2HF → F2 + H2 The formal reaction: electrolysis